I bought one of these
I run 2 or 3 chains per bike. One chain is ready to go, waxed, the other is in use on the bike. When the wax runs out (about 600km dry, 200km wet weather), I take it off and put the ready-to-go chain on. The other is dunked in the wax.

From time to time I suck the black metal particles out of the wax with a neodimium magnet.

This regime is far less time-consuming than anything else I have used. The waxpot is a double-wall heater so not much danger of catching fire. Beauty salons can leave theirs on permanently.