One year I was working as a privateer mechanic, good guy but not the sharpest tool in the shed...
Brand new set of RG3 A-Kit Showas ($9,750 out the door) for the race bike, was ready for the first bike wash after being built. Went to mix the ZEP cleaner that the rider brought with him and he stops me and said he already diluted it prior to me working for him. It was in an unlabeled 5 gal container that you could not see through. I pumped out 1/2 gallon into a 1 gallon translucent sprayer, which made the contents look very light purple in color as you would expect.
I didn't question him and gave the whole bike a liberal coat of what I though was the diluted ZEP. Turns it, it had not been diluted at all and it was straight up 5 gallons of industrial strength (commercial grade) concentrate. I didn't figure this out until I washed the bike and couldn't get the stains of the fork uppers and clamps. Thought it was hard water buildup, turns out it had etched the anodizing in the time it took to thoroughly cover the bike, set the sprayer down, and then rinse off....maybe 3 mins total.
I was heated, to say the least.
Moral of the story...I have never messed around with cleaners since that day. It's not worth it. Dawn dish soap and various scrubbing techniques are all that's needed.