By "burn it" I meant turn it into charcoal... Charcoal averages 80% carbon (range 50-95%), whereas depending on the type coal ranges from 60-92% carbon, with the purest type, anthracite, being 86-92% carbon
Given a mass production system would likely result in more uniform carbon content near the top of the range, I don't think it's unreasonable to suggest that they could be swapped out pretty easily
Seeding shouldn't be done on ratios - being the only one seeding 10 seasons of a tv show and getting it to 0.4:1 is way more helpful than seeding the same movie as everyone else and getting to 20:1, you're noy contributing anything there other than decreasing your bandwidth for things that aren't already at 100,000% availability