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So how long until I can recycle my scrapped PLA prints using my washer?
My 3D printing scraps were the first thing I wondered about too.

I have a box or two of just scrap PLA because they said it was recyclable/biodegradable. Not much about just how specific the conditions needed to be.

It can't be that hard to homebrew some sort of extruder to remake the filament, can it? Who needs tolerances?

Recycling PLA from 3D prints exists, without the bio part. I buy filament from a local supplier that recycles failed or unused prints into pellets, then rolls of filament.
I’ve looked at but never tried 2 things.

1, pla melts at about the same temperature as paraffin, people have used candle making kits to cast skulls or whatever. Seems neat to me.

2, similar trick, put the pla between two cookie sheets with weights. Heat to melting. This gives panels you can cut and incorporate into projects. Drawer bottom or robot body , that kinda stuff.

>It can't be that hard to homebrew some sort of extruder to remake the filament, can it? Who needs tolerances?

OK, it can still be disposed of cleanly. As in, dump laundry basket of PLA scraps into washer, add magic PLA enzyme detergent, push "PLA Dispose" button, and all of it stays out of a landfill.

There are a number of machines you can buy to do this. It's just expensive.
Cue the obligatory book recommendation, which I myself got from HN:

“Mutant 59: The Plastic Eater” by Kit Pedler and Gerry Davis, published in the 1970s. Explores the concept of a plastic-eating bacteria accidentally released in London, leading to a crisis as the bacteria starts consuming all plastic materials in the city.

PLA is made from organic starches --- not hydrocarbons. So it is not surprising that it can be broken down easily.
Don't think PLA is a good choice for coffee cups
But it's good enough for beverages: https://plabottles.eu/
The problem with PLA for coffee (and other hot beverages) is that it starts to get mushy at ~40oC and by 60oC it will likely melt completely.
I expect this may be used like Agent Orange was, but to destroy the enemy's cheaper 3D printed items.