Hard to reach internal parts are vulnerable too if you sweat a lot and carry against the body.
A very light oil like balistol... Or rem oil (though I am not a fan of rem oil) or other brands of light oil available in aerosol cans... They can really help protect the hard to reach areas in a firearm.
After a few cleanings, when I feel that I need to clean out the nooks and crannies that basic cleaning misses, here is what I do.
I break out an aerosol can oil, strip the gun down as much as possible without major parts removal, grips come off. (If I am taking out fcg parts, that is too far)
Then I spray out the action and all the hard to reach areas. I can see the hidden gunk dripping out. When I start getting more clear oil, I stop. Then I wipe the gun down as best I can.
Then I used pressurized air, caned air or a compressor set to about 10-15psi, and I spray out all the excess oil. When you are done, it will be mostly dry looking. A second wipe down and the gun is clean and all the parts, even hidden hard to reach ones, are coated with a thin layer of oil.
I then lube as I normally do, and then reassemble.