I got all but four sprinkler heads replaced yesterday. I didn’t think it would be so difficult, but with this house, and with my luck, I shouldn’t be surprised. There were about five different brands of sprinkler heads on the whole system–some plastic, some brass, some stainless steel–and the brass ones were bitches to get off. When I would twist them to try and remove them, the pipe they were attached to would turn instead of the sprinkler head. I had to cut each one in half down the center with a hacksaw, but only down to the steel pipe that it was screwed onto. Then I split the halves apart with a hammer and chisel until the entire head broke off, leaving a brass sleeve threaded onto the steel pipe. I had to make a vertical cut with the hacksaw along one side of the part still attached to the pipe, but I couldn’t cut too deep or else I’d cut into the threads on the pipe. Then I had to chisel the brass part until it broke at the cut and came off. If I had screwed up and cut into the pipe, I would have had to replace the whole pipe, which would have meant digging about a foot deeper and ruining my lawn even more.