I would take it apart and clean it. Pop the slide, push the pins out, gut it clean it and put it back together.
This a new gun? The brown (hopefully copper colored?) residue is the factory lubricant applied at the time of assembly.THanks for the tip, I found a spot in the slide where it slides against the frame that had some brown residue. I've only cleaned the gun once since I haven't had it but a week today lol. But it seems to be cycling like butter now.
I agree try CLP, I use it as a general oil & cleaner except for the connector I use the tiniest bit of white lithium grease.if you aren't using CLP that will help also.