For removing rosin flux from my board, should I use Acetone or Isopropyl Alcohol? I need an easily available solvent.
Acetone being used to clean circuit boards can be problematic. The biggest issue that I found was that it leaves a residue in the board that still requires several other cleaning steps to get rid of including IPA and hot water.
Even IPA can leave a residue as it dries.
There is also the problem mentioned in the comments that the acetone can dissolve certain plastics to the great detriment of your electronics assembly. I've seen it eat away the plastic winding wraps on small transformers as an example.
If you want real results to clean PCBs after rosin-based fluxes, you should use a specially-formulated solvent. Typically the solvents are based on IPA, but contain Toluene, Heptane, and Difluoroethane. Note - no acetone there.
For rosin based flux I clean with IPA (93%) and then hot water with a detergent. Then dry. That is for one-of's or a small number of pcbs.
Just adding to the answers because nobody's mentioned it yet - as well as melting plastic, acetone can strip the insulation off enameled (magnet) wires. So if you decide to use it be super careful not to spill any on motors or transformers!
Use methal spirit, it’s similar with IPA, the difference is methal spirit dry a bit slow. Sometimes people use it to clean windows
Easily available solvent: I have used for years trichloroethane, cheap, effective, and not visible residue.
Acid based would be Acetone.
ISO is more than enough for what I'd assume 99.99% of Engineering@Home Apps. to need. However that being said, they both work wonders on hardened, nasty, PCB, with flux everywhere. So if you want to rejuvenate your board, get acetone, less aqueous the better. Flammable, be careful like you would with a grenade. Use a gritted cloth and rubber gloves to slowly wipe away and immediately let dry your PCB. Circuitry should be ready for Re-Flux within 3-4 hrs if done properly. (Full-ATX Motherboard sized, etc.)