Greetings, and welcome to the forum! It's always good to have the Marines on board.
The relevant reference (which you are probably aware of already) is the USMC Flag Manual, MCO 10520. Section G.4.c says:
"Flags determined not to have historical value will be destroyed by the parent organization, privately by burning, with no suggestion of irreverence to its military or national significance, unless its retention as a display memento is desired by the organization."
"Privately" would imply that the destruction should not be a public ceremony. Obviously, the burning should be conducted with dignity.
You wrote: "I know that you must separate the Field of Valor from the Stripes, burning the strips first and then the Field of Valor . . ."
To my knowlege, there is nothing that says you "must" do this. Many individual organizations, such as the American Legion, have created their own ceremonies for flag-burning, but there is no law or regulation on the subject. The civilian flag code (which is codified in 4 USC 1) just says:
"The flag, when it is in such condition that it is no longer a fitting emblem for display, should be destroyed in a dignified way, preferably by burning."
Personally, I don't like the idea of cutting the flag into pieces -- it sounds more like some kind of pagan ritual rather than the dignified retirement of a national symbol. (That's just my opinion, of course!)
I hope that this information is useful. Again, welcome!
Semper Fi,
Peter Ansoff