@8bitforlife if convergence is ok on the grid you don't need to take off the yoke imo, you've probably reached a good stade.
Most of the work is adjusting between : OSD GEOMETRY - RINGS - CONVERGENCE STRIPS.
But remember, begin with perfect center, then adjust the corners in the end, if it's a little bleeding it doesn't matter you never play with a grid though...
At some point you will just want to stop because you will find your maximum level of will to make it look perfect, it can take ages, and one can be easily lost if there is no marks of settings...
Sometimes you want also to get some sleep and come back to see how it looks.
Cleaning the yoke is not a mandatory step, most of the time I do this when I'm sure it's pretty awful, if it's good enough better don't touch because you can always break something by accident even if it's easy once it's done.
To get rid of the yoke : Discharge the tube - Remove gently the neck board - mark the rings and unscrew them the pull them very gently to not to break the gun - unscrew the rings - get rid of the glue that holds the yoke to the tube - pull gently with some movements - the yoke will come out and let the tube completely naked - clean - remount reverse.
Remember :
It's just to get rid of residual old magnets which can bias the work, bit sometimes it's clean inside you can give a try to air can while screen is on a carpet or something like that but I am pretty sure you would notice if there was thrash inside.
I would rather make some stripes before doing this in order to finish the adjustment after remounting everything.
Before doing more hardware tinkering try some tests with a test grid with solid colors to see if it's burn-in on the same spot.
Try different setups, different cables...
Also remember burn in is FAR more noticeable on 31khz than 15khz because of scanlines.
Really your image doesn't look that bad.
