I took some pictures of my 1100, which may illustrate some things a little better.
On the magazine, pistons and cylinders, I use BreakFree CLP and I shoot the gun wet, meaning, sprayed on and not wiped off. Let that stuff soak into the metal. It keeps powder residue in suspension and will simply not bake onto metal. Here's the mag tube after shooting probably 125 rounds.
and here are those same parts with a single wipe with a cloth. No scrubbing or steel wool, just a cloth.
Here's the inside of the barrel extension. You can see where the locking lug has been riding hard, removing the bluing and actually dimpling the metal. I put a thin layer of grease on this area. (This is a 20 ga. Magnum gun, btw). You can also see that some bluing is missing from the flat part on the bottom of the barrel. That's where the forearm support rests, and a little dab of grease goes there as well.
This is the top of the barrel extension; a little grease here as well as a cushion against vibration.
This is the trigger group, and all it's assorted parts. The topmost piece of black metal (looks like the blade of a hockey stick) will show wear at that very top-most tip. Dab o grease.
You can also see on what is the right side of the lifter, is a large 'ear' that sticks up, near the front of the lifter. That is also another wear point.
Here's the front of the receiver where the foreend support (little wing-shaped little thingie, that sits across the action bars). You can see where the support has bitten into the receiver to make those elongated-"C" marks dimpled into the steel.
This is the action bar assembly, where the bolt rides. Every shiny spot there is from friction. Either very light layer of grease or oil.
This is the inside of the receiver, specifically where the barrel extension seats against a milled edge. That's another area that needs a little grease as it seems to take a pounding.
Even this little handle shows signs of friction wear. Lightly grease up both edges and pop it back in.
Now here's the bolt. Again, it has been sprayed with BF CLP and simply wiped off with a cloth. Almost looks factory new after about 10 seconds of wiping.
And that's it. The rest of the insides I use a very light oil along the action bars where they ride inside the receiver, and CLP on the trigger group parts. The trigger group, when it really gets filthy, I just use hot soapy water and a toothbrush, dry it with compressed air and then a little CLP. The trigger group doesn't get carbon baked into it, just powder residue (and vegetation, dirt from hunting) so it usually cleans up pretty easily.
I hope this helps. If you have an 1100/11-87, take a look at your gun for these signs of wear and see if you can't slow down the damage process somewhat.