Soda bottles can be washed and nearly directly used by 3d printers. Spiral cut the bottle, Thermoform it into a continuous cylinder (it folds it in and heats it to make it solid, then immediately fed to the printer or spooled.
If plastic recycling was actually being done and was profitable I don't think there'd be a Pacific garbage patch and pfas in my heart right now.
[1](https://en.wikipedia.org/wiki/PET_bottle_recycling)