The spray had a tough job... Used on a Mikuni carburetor, on an 18-year-old engine. From last year to this year it was also leaking (until I found a solution and took the time to repair it).

Before the 1 year of leaking, it did an okay to good cleaning job. Nothing became like new, but anything silver (body/cup) was cleaned to a respectable degree and without scrubbing, except for some pink spots. Especially on the jets, though, it didn't clean any of the black residue at all.

After the 1 year of leaking, it was tested to the limit. It handled simple/fresh gasoline residues excellently. However, the corners that had accumulated stuff all year (and I didn't have access to clean them in between) never got properly cleaned. I sprayed those spots several times, even scrubbed with paper, it just couldn't do it. I didn't use a brush.

So, if you use it even sporadically, it's fine, it does its magic. If you want it for heavier use, it might not be suitable. I say might because I only have experience with this one, I don't know how the others on the market are to compare, nor am I very experienced with this kind of product.

As others have said, be very careful when using it. I got splash back in my eyes (inside and around) and it was like someone threw acid at me... Luckily a friend was there to help. I emptied a whole bottle of water on my face and needed 10-15 minutes to recover.