Yes! you can recycle PET bottles into filament. You'll have to clean them, shred them and put them through a filament extruder. Somehow the hardest part of the equation is finding a grinder? which seems crazy, but it's true. There are plenty of filament making machines including filaextruder, filamaker, but the shredder, at least one that is not hand cranked is always the challenge in doing recycled filament!!