Now I just let them drain for a couple of days and then throw em away.
Back when I was servicing generators, some bigger engines had spin on filters that were bigger than a roll of paper towels. I used to think about how much oil was going to landfills in these things. Not only were they big, I was changing lots of them every year.
I ended up making a filter crusher for my shop press. Basically, it was a steel sleeve the filter fit into with holes in it for the oil to run out and a top that crushed the filter. I'd get quite a bit out of these big filters. Plus, since we heated the shop with an EPA approved waste oil heater, every little bit helped.