Have you considered using a small retort inside your woodstove?
I've done this myself using a small (about a quart or so) stainless steel can with a few tiny holes punched around the edge of the lid and then placing it upside down onto a bed of embers inside my dads tiny Jotul 602n stove. This works great and gives you 100% ash free char. The char being ash free is quite important to me since the soil here is already leaning towards the alkaline side so I rather not add any ashes to it on purpose.
Retorts are especially nice to pop into your stove at the end of the evening because you don't have to worry about the stuff inside them to smolder down to ash if you leave the retort in your stove overnight.