IPA versus IMS?

[ppppenguin]

IPA (isopropyl alchohol, formally propan-2-ol) is readily available. Or at least it should be since it was in huge demand for making hand sanitiser and prices shot up. IMS (industrial methylated spirit) is not legally available to individuals in the UK but some people may have it available informally through their work. IMS typically contains 90% ethanol, 5% methanol and 5% water. It's a constant boiling mixture which makes it almost impossible to distil to recover pure ethanol.

They are both short chain alchohols but not chemically identical. IPA is certainly used as a paint thinner. I think it's very like that IPA can be used to thin shellac. Try a small amount first.

https://en.wikipedia.org/wiki/Isopropyl_alcohol
https://en.wikipedia.org/wiki/Denatured_alcohol (rather US centred view)