Another helpful hint, don't dump your ash in a trash can until you're SURE it's completely cold. I've ruined two plastic cans this way, both with gaping burn holes in the bottom.
Have a yard? Potash is high in potassium, good fertilizer for some plants. Do your research though, too much potassium can scorch your plants. You can also use Potash in small amounts with your compost pile.
Happy heating!