No dunking, and make sure what you’re buying is mostly alcohol (> 95%) and not water/alcohol mixtures often used for disinfection. Using in combination with e.g., a toothbrush is probably your best bet. IPA (and acetone) can strip some adhesives and cause certain kinds of electrical insulation to swell or dissolve, so a targeted approach is better. IPA is flammable (though less so than acetone), so be careful/well ventilated when allowing parts to dry, and ensure parts are fully dried before reconnecting to power.
IPA itself is only about twice as toxic as ethanol and certainly less problematic by inhalation than tar in the long run. I wouldn’t bother with a mask mostly because it won’t do shit unless it’s a cartridge respirator. However, IPA can sometimes facilitate skin absorption. IDK specifically about tar buildup but recommend wearing gloves (disposable nitrile is fine).
Yep, sorry for going between terms. Also, if the confusion stems from just calling it “alcohol” at one point, I was using the word in the more general chemical sense (molecules containing a C-OH group), a class to which isopropanol and ethanol belong.