I really don’t think submersion is necessary. On anything but proof coins, a gentle ‘mop’ over the surface with a saturated Q-tip will do! Sacrilege I know, but it works, and even on the finest fields, reflected under natural AND artificial light, you’ll perceive no difference…dig out your 1967 pennies and see for yourself.
The one thing I would say, however, and I shared it on here a long time ago…never re-dip your bud into the acetone, otherwise, by the end of the bottle, you’ll be layering more junk onto the coin than you’re taking off!