Pj how did you get the resin out of the semogue? Does the plug pull out or do you have to scrape it out?
Basically the latter. Cut the knot off leaving enough sticking up to be able to grip it with some pliers if needed. Drill a fair sized hole through the centre (try not to punch through the bottom of the cup) to get a start and then just use screw drivers, small chisels and pliers to pull hair out untill the hole is big enough to get sand paper in and after that just gently scrape away. I used a pretty gritty sandpaper taped to the end of marker pens. As the hole gets bigger you just roll on more sandpaper or go to bigger sized marker pens. It's quite a lot of work. Don't forget to tape up the outside of the handle to protect it against damage, droppage etc. I generally use electrical insulation tape as it's fairly easy glue and doesn't leave a residue. You still might lose the sticker! Brushes look better without them anyhow.