I accidentally put the mark on my father's Colt. Fortunately, the gun was polished stainless, and the mark polished right off with Flitz. The gun had never been fully disassembled before when I did it (and it's a Combat Commander with a 70 serial number), so everything was a little stiff going back together. Now it goes together with no problems.
My father never field strips his guns. I'm the only one who's ever taken them apart.
There's 2 schools of thought for stripping the 1911. One is to push the spring endpiece in and rotate the bushing. The other is to simply pull it back, push out the slide lock, and slide the whole thing forwards and off. The latter way is usually easier, though you have to be careful to not let the spring bow out while removing the slide. I tend to favor the latter method, especially since my father's 1911 has a Group Gripper full-length guide rod installed (one of the upgrades I put on to fix its accuracy issues). The spring isn't going anywhere, and normal disassembly would require tools.
