A couple of years ago we had a shooter on temporary duty here in the SF Bay Area.He used a cardboard box with rubber mulch.I always have used duct seal.When he went back home to Ohio he gave me his box.I went to the post office and got some shipping boxes and filled three of them with the mulch he gave me.I taped the boxes with duct tape from HF.As the boxes got shot up, I taped some more.Finally time to get new boxes and re-cycle the mulch.I poured the mulch with pellets into my 50 gallon vacuum cleaner base and filled it with water.The mulch floated to the top and was easily scooped out for re-use.The pellets were melted into lead ingots for later usÖGood stuff..
I read somewhere, probably here, about a guy who used his shop vac to not so good up the rubber mulch out of the box, leaving the heavier lead behind. I like that idea. I can add a HEPA filter to my vac so I won't be blowing Pb and rubber dust around. It would keep the mulch dry too.
The rubber opens a channel if I stack pellets eventually hitting back plate in 4-5 shots, very loud