I was wondering this myself just last week.
You can recycle EPS , if you can get it back to the manifacturer or find a council that collects it. i haven't been able to.
Several ideas I've tried ;
Make your own cavity closers with it , al-la Mike Georges method (probably the best so far)
break it up into small bit and half fill bag with it , then use them to top up loft insulation
break into even smaller bits and pour down the top of empty cavities when doing minor works like
frenchdoors with side lights etc.
slivers can be good for packing round window heads etc .if you dont full foam

Find someone who makes composite parts. I use the "lost foam" method all the time to mould complex composite shapes, using small bits of EPS. Buying large sheets to just cut them up for small parts always grieves me somehow....................

stick the bits together again!

Feeding them through the garden shreader. Thats a job for the apprentise if ever i heard of one.
I been told that if buried in any way the loose balls have a habit of floating in wet weather? but if im honest i was hoping to use them in the garden some how? maybe ill hide behind the shed for 10 years in the vane hope ill use them sometime

Slightly related, I was wondering also how people avoid EPS pollution. How do you make sure all the little bits don't float off out into the environment when cutting and handling?

Don't forget Freegle (www.ilovefreegle.org) which split away from Freecycle after that big falling out with its US HQ... We use both in our area.

Rgds

Damon

I have used offcuts of poth PUR and EPS in the voids of internal studs (usually in loft conversions) I've also left bits in inaccessible roof voids on top of the other insulation