Ahem. Burn them to create CO2. Move a couple of water asteroids their way. Seed the planet with plant seeds.
Earth 2.0
PS. Always thought fossil fuels are not fossil fuels. I think they are asteroid juice. Star juice. Either you understand or you don’t, but coal is charcoaled forests. Gas and oil.... cometary remnants.
I think hydrocarbons are a product of high temperature high pressure chemical processes occurring in the earths crust and mantle.