I love the "50 gallon barrel of death" approach, and the peanut butter and plaster of Paris one, as well.
A product called Golden Malrin is an excellent rat poison, but has the same problems as anti freeze, as it will kill whatever eats it, and probably whatever eats the dead rat as well. You get a decent sized tub for a few dollars, and I gather it only takes a little.
I have used poison against them. My choice was one that kills the rat but is supposed to be harmless to an animal that eats the dead rat. The chemical name is bromadiolone. One of its brand names is One Bite. I already had a package of it when I ran across the PB/plaster of Paris approach, and have still not used up the bromadiolone, so I have not tried the other.
On the other hand, the rat tunnels all disappeared after I put some bromadiolone down a few. I do have dogs who actively hunt and kill rats, so am not really sure which one got rid of the problem.