Help finding $50-budget version and info, my brain is fried

Im off grid-ish here and lots of other stuff vying for attention, so could use a little boost--what should I be looking up for handling ash buildup in my #10 can style rocket stove...? It barely boiled two kettles of water so far.  It's only for cooking, and mainly proof of concept.  I keep finding info for heaters, I'm not trying to heat people just soup.  

The design is more or less the approveccio one except I couldn't get a rectangular big can, just a #10.  (We have a rectangular can that had paint remover... isn't that rather toxic even after burning out the paint remover?)

I'm probably doing a lot else wrong, but it's temporary and operating in rural area.  Just trying to show people we can do things without propane, using our surplus of twigs.

Thanks so much!

Hope this picture comes thru

Ok, getting it lit directions I googled worked but only with putting biomass in the top down the chimney, so that's a part of why it got so stuffed up.  And to use pitch wood (ashy and creosotey, I gather)

Is there a better way to get it going?

Tear up birch bark into little shreds said a guy who's started a lot of fires.  Will give it a try tomorrow!