Trust me, you'll be thanking me...
That annoying half inch of wax that's left at the bottom of a scented candle, when the wick's too short to light and even if it wasn't you'd burn your fingers trying - scrape it out into a small tin and place on top of wood burning stove. Light stove and voila! My whole house has smelt lovely since about 4pm this afternoon. If the candle was already in a tin you don't even need to do the scraping out bit.
You're welcome 😉
(Ps sorry if you haven't got a wood burning stove - radiator might work?)