In case it helps:
We use the 50/50 mix ATF & Acetone in our shop. The master mechanic is a retired bus mechanic, and he showed up with a squirt can you can pressurize with air - can't remember what it's called. Anyway, just pull the trigger and it sprays - works great, and doesn't evaporate. Think the air squirt cans are quite pricey, but very nice to have. And yes, practice good sense - wear eye protection, the penetrant splashes back typically.
-Michael
