Rumbleseat trick of regreasing a throwout bearing?

[alchemy]

Years ago I read in Rumbleseat’s tips how he would drill a small hole in the outer radius of an old-but-good throwout bearing to add more grease. He said he would then screw a small screw into the hole to seal it.

Has anyone here ever done this? How did you make sure to not get any swarf in the bearing? How long can the screw be? Do you fill the bearing till it takes no more?

I have a couple old bearings that aren’t loose or crunchy and might like to try this. We all know how they don’t make good bearings anymore.