This video shows you how to completely disassemble, clean and reassemble the upper. The video has some very valuable tips on how to clean and maintain your upper.
Warning! This is not something you should attempt unless you have confidence in your technical skills. I recommend watching the videos several times before attempting disassembly until you have a good understanding of what to do. Don't send your gun in parts to me... Got it? Wear eye-protection!
Before you do this, make sure you have all the tools needed:
1/16" Pin Punch
Very Small Flat-Tip Screwdriver
Gunsmith Hammer
Cleaning Rag
Q-Tips
Slide-Glide #1
Brake-Cleaner
Tech