Brother and I have a Kenmore 0.9CF, 900W microwave with rotating glass tray support, which I bought from a now-dead Kmart post-Christmas 2017. (Our parents passed in 2015 and '16)

It's become more heavily used in the last 2-3 years bc the adjacent gas oven won't light anymore (age north of 20)

Spots in the roller guide channel have developed, which from cleaning today I discovered were stripped of paint. (At first I thought they were caked-on gunk, no such luck.)

The fact that the glass is covering them, as of now, is preventing something more catastrophic from happening, but the paintless spots do, depending on the combined weight of the item to be heated + another china plate used to keep spatter largely off the glass, cause the roller guide to get stuck while the drive gear continues to turn the glass.

I could trade in the china plate for one that's lighter, which I don't believe I have anymore, to reduce the possibility of the roller guide wheels getting stuck, but I'd rather find something easier and less costly than a can of appliance paint of which I'd likely only need a little to cover the spots. Brother is thinking something not as hazardous as paint can be used, that enables the roller guide to turn and -- if the glass stays in place -- won't get blown all over the interior.

If it doesn't work out, he has a (smaller) microwave he used to use in the apartment he had before he moved back in with me.

What path should I take here? Thanks.