Once they're all captured, I think it would be best to put them in a giant blender and frappe the hell out of them.
Is it a good idea to seek out, capture and imprison all spammers? Should we then dump them into a big bowl of custard (with Jeremy Clarkson and Donald Trump (who will be there already))?
Seems like a lot of effort. How about just a summary public flogging for each one. 20 lashes or so. It's quick, cheap, and gets the point across. You could charge admission, sell refreshments, T-shirts and whatnot.
Perhaps additionally, destroy their computer devices.
Not custard! It's too good for them!
Ok, but the custard has to have mould on it.