Wet & Forget Mould, Lichen & Algae Remover, Outdoor Surface Cleaner, 5L

I used this in November 2024, yes that right and I am writing my review in May 2026. A whole 18 months later. Firstly those who thinks its cleaner like washing up liquid! Its not, you apply and leave it to work, you don't rinse it! Hence the name! Wet and Forget. On the container it even says results could take up to 6-12months. Do not expect results in hours, days or even weeks if they are stubborn! I spent a good 3 hours spraying it and noticed 3 months later that my back garden slab area looked less grimy, another 3 months and the front paving looked a little less grimy to now a whole 18 months later and the front paving is back to its original colours and you can clearly see the red/yellow/grey bricks. The back garden grey slabs looked bright and the crazy paving area no more moss. Like most I wasnt expecting a miracle but I am pleasantly surprised. If you havent the patience and want results fast then this is NOT the product you seek.

This is the second time I have purchased wet & forget and the results have been favourable in terms of eventually getting rid of algae, lichen and even moss for a period of time. I originally bought this to treat my block paving drive as I had what I'd described as white chewing gum stains and black spotty marks all over the area. I tried power washing and scrubbing with detergents but nothing seemed to work and then a friend advised to get wet & forget. I was a bit dubious it isn't a cheap option but I decided to give it a go and after 3-6 months I realised pretty much all the stains had gone! Now it certainly does not work overnight but I treated once and left (and genuinely fogot about it)... all the marks had gone, see attached pics of before and after treatment. Since then I have used my second container on my roof and even on a very old roof with high levels of moss growing. Here I did remove some of the moss with a plastic scrapper but the rest was down to spraying this product. It is so simple to do, just dilue 1 part wet & forget to 5 parts tap water, mix and then spray generously on the affected area. It is advisable to do this is dry conditions or when rain is not forecasted that day. Then wait, and over time you will see a difference. To conclude I am going to give this a full 5 stars it does actual work well. Only time will tell if it continues to work but in the case of my drive it remains clear of these marks after over a year+ period so I am genuinely happy with the results. It is not a cheap solution (there are lower cost alternatives which I have not used) but this one certainly delivers.

Small amount for the price but dilutes down so not bad value. Does not smell chemical and the bottle was well packaged on arrival, easy to apply with a spray bottle and no leaks. Seemingly takes a while for removal but our green algae on the wooden fence slats went almost instantly. It looks really good now. Was worried about the effect on nearby grass but this seems less damaging than other chemicals we have used in the past. The slats now look much better. Really effective and hopefully long lasting. This should avoid us having paint the fence this year. I did most of our fence and also a decent amount of decking boards, spindles and siding with the smaller bottle. A big bottle would easily do a whole garden.

Unbelievable results!! Treated our outside concrete steps that lead down from our kitchen (building is 1902) and this does exactly as it says - ‘wet and forget’ ! Started to see results after about a week, we are 5 weeks in now (July 12th) and it’s just keeping working no more pressure washing mess!!

Excellent however you need to follow the instructions and be patient ! The product reacts with the weather elements over time and it got rid of the majority of black algae spots but it doesnt take days, it takes a few months to react. We saw the product lightening the patio slabs about 2-3 months after application. We have just jetwashed the patio this month and it was so much easier than last year! We're so pleased, we're buying another batch to keep on top of it as the drainage for our small patio area is not that good. This will be the second batch in two years. The photo was taken when we first bought our house 4 years ago and just jet washed the patio. The second photo is the patio jet washed about 8 months after we applied the product about 2 years after we bought the house. Cheaper than getting someone to lay a new patio but yes, you do have to wait for results!

**Scroll down to the very end for my UPDATE. To any reviewers that discredit my review and claim it's not real, sounds too vested in this product. Here's my HONEST original review: Having just used this, I can honestly say it looks worse on our indian limestone. I'm hoping it look better soon. Having done a lot of research before buying this brand, I've learnt a few things: • If you plant to treat lichen I.e. black spots on your stone, do a second treatment in rapid succession after the first. About 20 minutes apart. • The product states to make a mix of 1 parts concentrate to 5 parts water. Make a higher concentrate if you want a more rapid result. **Some reviewers have said it can take atleast six months to notice a difference. • Power washing after using this defies the point of using this product. Not only will you get this toxic substance airborne with a power wash, but, using a powerwash alone, will gain the same result without buying this solution. • I'm going to reapply another treatment tomorrow. There is no way I'm waiting six months for a noticeable difference. You might find you need to order two drums if you want to apply a second treatment right away. This drum makes about 7 applications. i.e. one full watering can (10 litres) equals 1 application. This means 1 part solution to 5 parts water. • You would be able to extend the usage of the solution by using a knapsack, but you will end up getting the solution in places you may not want it, due to the finer mist. Such as a fishpond as in our case or on our ancient dry stone wall which is teeming with beneficial insects which pollinate our fruit and veg. • The substance is toxic to wildlife when wet. Pets should be kept indoors, they say, until it's dry. Yes, it will make a difference to the local fauna in the shorterm, anything that crawled, slithered or scuttled on it, lost it's life. **ALL OF THE ABOVE WAS DEDUCED DIRECTLY FROM THE INSTRUCTIONS ON THE DRUM. IT CAN'T BE DISPUTED!!!** **UPDATE** Just to make it clear, I followed the instructions to a T: Application on a DULL day. No forecasted rain for the prescribed time. This Product takes MONTHS to work. This is my honest review. I gave up seeing an effective difference with this product in the short-term. By short term I mean 3 to 4 weeks. I couldn't see it making a rapid turnaround even if I left it a month or two longer. If you want an immediate difference, to enjoy your garden, for example, in the summer, you may have to resort to more drastic measures. Here's what I did: • I used a bottle of undiluted household bleach to one slab as a "test slab". The bleach cleared the slab by the following morning. • I then applied a 25/75 solution to the rest of the slabs of bleach to water. The result is far better than this solution. The 25/75 mixture didn't give the same results as a 100% bleach. It is however very passable and looks like one year old slabs as opposed to the 'freshly laid' look I was looking for. So to round off, if you are resolved to using this brand's less abrasive solution, plan ahead. Preferably 6 months in advance. If you want an immediate change, try another mixture. The bleach method worked better for me. I really hope you've found this useful. :)

I was really concerned I was buying something that was a waste of money. I had recently had a block paved driveway. It is a big area. The block paving company advised not to pressure was it as it damages the face of the brick I took no notice and decided to do it anyway as I had always pressure washed driveways. He came back to do some work and mentioned how good this stuff was. As pressure washing makes a mess everywhere I decided to give it a good. Well, it’s BRILLIANT. Noticed it within 24 hours and now 8 weeks later the bricks and my garden cement posts and wood around the garden look like new. This is a game changed. Cannot recommend highly enough!

Works well and overtime it keeps pavers clean

This product is the best on the market and worth the cost. My fences have looked great for years with a treatment every 5 to 7 years or so. Plus unlike high pressure cleaning, it doesn't remove the pine wood treatment meaning it is clean but not exposed to termite damage.

Trying different concreat mold remover over the years .this is the best one i.ve got so far.

This was sprayed onto a heavy lichen infestation and had started working by the next day with some lichen falling off. Very happy with these results

Great for mould and algae removal and easy to use.

Great product and good value with Prime