Maryland: What can my mother do to remove a ungrateful 20 year old from her house?

Legally, you can't do anything but file an eviction. You can't simply move his stuff to the curb, b/c that is considered unlawful eviction. You might think your mom can't go 30 days waiting, but believe me, she can. It's already been how long? What's another 30 days? In the meantime, you and your mom need to lock up any valuables that are left, and don't make his 30 days a nice stay. I wouldn't allow him access to the tv, fridge, whatever. I'd make him as miserable as possible, so maybe he'll leave on his own, or at best, stay gone as much as possible. But go ahead and get the eviction filed NOW, don't wait.