I pulled of a plug off of my compressor and notice a lot of rust in my new compressor. So , how can I keep the moisture down inside the tank? Maybe a couple of sprays of DW-40, not doing any painting any time soon. I do drain it regularly also.

Another question maybe you can answer, Why are the air filters on compressors so restrictive? Are they meant to be like that, or can I put a bigger air filter with no problems ?