I use a home made screen to do the initial sort of rubber mulch versus pellets from my traps. That works well but small pieces of mulch go through too. I tried water to sort the small stuff but rubber mulch is heavier than water and it's messy. Somebody suggested a vacuum and I tried that today. It works much better. I used an old Ryobi battery powered shop vac. Initially I had a brush attachment on and got most of the mulch out that way. At the end I used the end of the hose but had the hose vertical. Pellets got picked up but fell from the hose when I shook it and when I switched the vacuum off. I was surprised at how well this worked. The picture is about 4.5 lbs of pellets with very little mulch.