Take the compound brush and the courses (lower number, 220) compound and apply to both the receiver and slide channels.
Assemble the slide onto the receiver and be careful as the compound will "scrape-off" as you marry the two parts. With the slide to the rear, take the excess "scraped" compound and apply it to the inside rails through the ejection port. Slowly move the slide forward applying the compound the full length of the rail.
With the compound applied, start the slide cycling going the full length of travel. Avoid slamming the dust cover against the feed ramp/barrel lug machining.
You will feel the compound cutting the high spots with a grinding feedback. Keep cycling until the feedback disappears. If compound is forming on the outside of the slide, use the brush to re-apply it through the ejection port until the "grinding" feedback ceases.
The compound will consume itself into a liquid media darkening with the suspended, removed metal. When you are sure it has stopped working, cycle the slide another 50 times.
Separate the two parts and using the bucket and the Brakleen, completely clean the parts until the compound is gone.
Blow dry the parts and inspect for wear areas. This will show you where the high spots are located. Re-apply the 220 grit compound insuring the high spots are well coated. Following the above step, continue until the current compound is spent.
Repeat the step at least one more time with the 220 grit for a total of three applications.
Now repeat the above using the the two remaining grits, 320 and 660 for a minimum of 9 total applications. Do more of each grit if needed. NEVER
go back to a more course grit! It's a waste of time and money. If you do each grit three times, it will be done. More is never better when you are removing metal!
Do a final wash of all parts with the Brakleen followed with soap, and dry completely. Coat all parts with CLP and reassemple your 1911.
DO NOT LEAVE YOUR CLEANED PARTS UNPROTECTED FOR ANY LENGTH OF TIME!
Rust (oxidation) never sleeps.
Let me know how this worked for you.