It's amazing, looking back, what you could easily buy over the counter: I remember in the late-60s as a schoolboy going to the local chemist and buying a pint(!) of Carbon Tetrachloride for cleaning switches, and Trichlorethylene (colloquially called Trike) was equally easily available.
There were versions of such solvents deliberately marketed at the man/woman-in-the-street too: little glass screw-lid bottles with a cotton pad in the top called "Dabitoff", and also 'Thawpit'.
You could also buy stuff like 'Killed Spirits' from the chemist - very good as a flux for soldering copper pipe but also great for making holes in your jeans/the carpet if spilled.
My favourite one though was Potassium Hydroxide: I bought a packet of crystals of this when experimenting with 'electrolytic rectifiers'. Mix the crystals with water [it gets very hot!] then try different metals as anode/cathode to see which gives the best diode-action. it depends on the formation of metal oxides on the two electrodes, sort-of like a 'wet' version of the copper-oxide rectifiers. The electrolysis involved can produce some extremely noxious fumes - and don't leave such a beastie running unattended as they are prone to boiling-over (as I found out).
I never did make a really-successful electrolytic rectifier
