Hi:
It's not really parts wash, it's carb cleaner.
It works great at dissolving varnish in the carb, and can be used without taking apart carbs, and won't harm o rings.
But, it won't dissolve oil or grime worth a #$%*. In that respect, it's nothing like spray carb cleaner.
I was very dissapointed because my carbs had no varnish, but they were ultra-grimy from leaky top-end oil. So, I actually used gasoline to soak and clean grime, then soap and water to remove residue.
Don't use Berrymans ChemDip, unless it's for internal parts. I used it on my carb bodies and left it in there for days and it etched the aluminum and looked horrible -- I ended up getting them bead blasted to restore some kind of bright finish.
out
Zeke