I just use OMS. It takes gum right out.
I use matrix release works great I ad about a 1/2 cup to my pre spray and it will usually come out during the rinse with the wand if it doesn't than I go back to the gum spot and use some release directly on it and use a skark tool and really wand that area. Almost always it comes out with the wand during the rinse.
Citrus-solv works well. Dab it on and it will dissolve then extract.
Or zipper.....and a kero heater!!!!
I usually never have trouble removing gum, and I remove a lot of it in the restaurants that I clean. The heat from truckmount melts it away, I do have to go over it a lot sometimes 10-12 times as the gum spreads around and sticks to glide on wand.
I use De-Solv-All , and the Shark Tool , however sometimes it may need a second application , either way , never met a gum spot I couldn't get out. Movie Theaters are horrible and restaurants as well. Good Luck!
The Gun and Cuff. 30 to 60 seconds per piece and no dangerous chems.