Yup, breaking in a motor is just like NiCd/NiMH battery maintenance and the correct way to shut off a nitro engine. There's about 800 different ways to do it and they're all wrong
My Old Man was a slot car guy when he was my age, and I've been doing my own motor tuning on Reedy MVPs and Stockstars for years now. The quick-and-dirty way to break in a motor is just to drive it around real easy for a pack or two. Driving in something like an empty street or parking lot, slowly rolling in the throttle, no sharp turns, don't touch the brakes or move in reverse, and keep it under 3/4 throttle.
To break in my race motors, I run them in a tub of cool tapwater on a 3.3v lead from an old hotwired computer power supply. I put a drop of lube in both bushings and a drop of my homemade "Liquid Talent" comm drops on the commutator before running the underwater break in for about 5 minutes. Once that's done, I blow the thing out with compressed air, flush it with brake cleaner (motor spray), blow it out again, and re-lube the bushings.
On Reedy motors especially, getting the commutator cut on a lathe from the get-go makes a HUGE difference. It seems like a lot of Reedy comms have unevenly placed segments, so you get this woodchipper effect on your brushes and the motor runs like junk. But a session on the comm lathe right out of the box to smooth everything out solves 80% of what ails the Reedy motors, from my experience.