HF is scary but not that insane and not impossible to get without a license (in the US). You can get kits to etch glass which contain in-situ HF (armor etch for

HF is scary but not that insane and not impossible to get without a license (in the US). You can get kits to etch glass which contain in-situ HF (armor etch for example). You can produce your own by obtaining fluoride salts and adding acid - though I would NOT recommend doing this without having some sort of lab chemistry training. There's a line between "demands respect and thought during handling" and "reckless/insane". Having a properly ventilated workspace, and knowing how to handle dangerous chemicals, I would say HF is dangerous but not insane. Borderline insane for a hobbyist would be things like generating primary explosives/peroxides or toxic gases: cyanides, phosphines, hydrogen sulfide, ketene. I worked as a lab chemist for years and even with a decent home lab, I would be loathe to do any experiments which generates toxic gases in anything greater than 100's of mg quantity, because discharging your vent hood becomes a big concern. I've heard stories where someone accidentally acidified some cyanide (in a hood) and it killed a bunch of pigeons on the roof. HF, eh, that's fume hood and PPE territory. Neutralize with calcium hydroxide, evaporate it in a hood to salt, and dispose as you would other solid chemical waste. It's just fluorite mineral at that point.