One way you could do this - and while not simple, should produce a fairly pure product.

shred the floats and then dissolve the plastic in acetone. Pass the solution through a very fine sieve, probably don't need a molecular sieve, coffee fiter level ought to do it.
Then evaporate and recover the acetone and you should be left with a fairly pure block of abs that could be turned into printer filament.

Now acetone is dangerous stuff. You don't want to breathe too much in and it's also highly flammable.
So this isn't a process you could safely do in the equivalent of a garden shed.

But if you used the right equipment, and used solar power to warm the solution to recover the acetone (it evaporates at low temps. so heating the solution to around 40c would force the acetone off pretty quickly.
You could also use solar power for the agitator in the vat where the abs is added to the acetone and dissolved.

Get it right and you could end up with a near closed system that constantly reused the same acetone.
You would have to add a little extra acetone every now and then, but your main consumable woud just be the filters.

That's how I'd do it.