I'm always sceptical of snake oils
Seen this thread on bob is the oil guy started by one of their writers and moderators.
There are some other write-ups about that test too.
Couple of months ago, I did a compression test.
Seen that my piston tops were completely covered with carbon again. It had been only a few months ssince the new pistons and rings...
Thought I would try the Gum Out One-N-Done.
I was going through one bottle in the tank when I dis a leak leakdown test. I noticed that there were flakes of carbon missing.
Now I did replace my MAF sensor shortly after this which corrected a 6% - 9% positive fuel trim.
Anyway, i proceeded to use another bottle of One-N-Done.
When that tank was used up, I pulled the plugs to look again.
I have attached the pictures of what I seen.
I was stunned.
Sorry, I don't have pre usage pictures.