I’ve got a clogged sink, and have been reading the labels on a bunch of different products lately. I’d always assumed that they were a strong acid of sorts, which would dissolve whatever sort of material was built up in the pipes. But I’ve noticed that a lot of these products specify that they’re non-corrosive, so I’m not sure what other sort of mechanism may be at play here.
If you have PVC drains (probably unless very old) most likely you can unscrew the fittings by hand, very simple. Take the trap off (the curved part) and just pull out the clog. It’s not hard at all, take photos as you dismantle it if you’re worried about remembering how it goes back together.