If you ever get stuck in a blackout without candles or a flashlight 30 minutes might be stretching it, but a regular sized crayon will easily burn for more than 15 minutes. The paraffin used in crayons is very flammable, but slow burning. Handy to know!
or microwave a small amount in the microwave for 5 seconds or less. (to soften a whole stick, do 10 seconds, for 2 sticks, 15 seconds - this works as well as letting it sit out and it's sooo much quicker - just don't go over a few seconds or it'll melt)