Anytime the gun needs a good cleaning i do the magazines. It's easy, fast lets me know if i need to clean more often.
I use nothing but dry lube. Not any old so called dry lube. No graphite, silicone, petroleum base stuff. it collects crud in the mag.
I use mil tec 1 dry lube or mag slick. It does not gather crud like other lube will.
Militec-1 Lubricant-Grease for Firearms-Autos-Sportsmen