I like the way you think! On one hand I love the idea of repurposing oil filters, an item that currently is disposed of as hazardous waste. On the other, I shudder to think of used motor oil with all the contaminants being burned off into the atmosphere. Of course, now they probably sit in a landfill somewhere and leach into the local water supply.

You are right - it feels like the way oil filters are manufactured should lend well to repurposing. If not cleaning and reusing in another filter application, than some other apt use.

I'm a backpacker, and it strikes me that the design is close to alcohol stoves. Both my Trangia stove http://en.wikipedia.org/wiki/Trangia and my beverage can jet stoves http://en.wikipedia.org/wiki/Beverage-can_stove have a similar configuration. But again, I would worry about high heating the residue.

It looks like there's a business in collecting for a fee, crushing and cleaning, then recycling at weight:
http://www.usedoil.com/filter1.html

I look forward to hearing other ideas!