I scrape as much off as I can with a putty knife.
Then if I can, a wire brush.
After that it goes in the cabinet.
I've not had an issue reusing/recycling play sand and I even scavenge what I can when I blast outside, over a blue tarp.
Even at $3 a 50 pound bag, it goes quickly and adds up. I can usually reclaim between 25 and 40%.
I do sift it before reuse (actually before the first use as well). It's tedious and time consuming, but necessary or you get blockages.
