I used big traps. We lived in a middle income neighborhood and had just planted a little garden. We noticed the little plants were getting eaten down to the surface of the ground. We set traps and caught 8 or 10 rats. Our dog caught 6 or 8 more, and I killed another 8 or so with a pellet gun.
One night about 10 I was going outside to check on the dog but unknown to me at that time the dog had a rat cornered against the back door. When I opened the door and walked out, the rat came inside. I heard my wife screaming so I went back inside to check. We tried to shoo the rat back outside be he remembered the dog and wasn't about to go back outside, so he turned and ran to the other end of our house. My wife said we were not going to bed until we got the rat outside so I started searching. I finally found the rat under the living room sofa, then he ran into the bathroom and ultimately jumped into the bathtub. I closed the sliding doors and stood on the toilet seat to look over the sliding doors. The rat climbed the hose on our shower and jumped on my shoulder. I knocked him off but a little later he ran up my leg. I finally killed him with a pellet gun. This whole time my wife was on the phone with our neghbor giving a play by play commentary. Anyway this pretty much ended our rat problems.
A year later my wife suggested that she wanted to be single again and I should find a new residence, which I did. A month later she called and told me she had a rat living in her garage. I told her to set a trap before the rat decided to chew on wiring. One night she called me, in tears because she had trapped the rat but couldn't kill it. She wanted me to come over with my pellet gun and kill the rat. Now this pellet gun is a single pump Daisy, made for target practice. It is big and menacing looking and even though it doesn't have much power it is enough to kill a rat. So I come zipping late at night and go into the house carrying this big menacing looking gun. Five minutes later I come back out with this big gun, get in my car and drive off. If any of the neighbors had seen that I'm sure they would have been very suspicious.
A few years later I'm in my new house in an upper class part of town, and a rat decides to live in my garage. He ignored my traps for a long time, so I decided to get serious about this. My mistake was keeping my dogfood in the garage during this same time. I decided if I put the dogfood in the house then the rat might be more interested in the traps. I picked up a medium size bag of dogfood that I had not opened yet and discovered that it was now only half full. With the dogfood out of the way I caught the rat pretty quickly. This was the biggest one I had seen- the body measured 7 inches long and the tail measured 9 inches long. That was over 10 years ago and I haven't seen a rat since.
Anyway, the spring traps worked well for me. Peanut butter is a good bait because it can't be removed from the trap easily. I always played with the traps a bit so they were fairly sensitive, and if I was careful I didn't have any problems with catching my own fingers. Also when I was setting them by my garden I found that I had to tie them to something with a piece of wire so they didn't get drug off.