Step 1: Light the lighter and set the milk jug on fire.
Step 2: Milk jug starts to melt and burn.
Step 3: Milk jug collapses on itself.
Step 4: Milk jug 3/4 gone; reduced to melted plastic, carbon dioxide, hydrocarbons, and water!
Step 5: It keeps burning up and disappearing.
Step 7: It’s almost entirely gone.
Step 8: All that’s left is a little resin left in the coals.
The fire has almost completely disposed of this milk jug that was previously just trash that otherwise would have lasted forever in a landfill. The fire will eventually burn out, and what remains will be burnt up in the next fire.