Best way to fix dots on a Focus 40?

Hello everyone, I've had a few Focus displays through the years, first on an ElBraille 14, and now on the ElBraille 40. This Focus is the latest one at the time the last ElBraille was released. The ElBraille itself is no powerhouse, but a decent enough machine for every day stuff. I over all like the Focus displays, but an issue I've had with both the 14 and the 40 is dots that get sticky, or don't want to pop up. The only other displays I've ever used were on the Braille Lite back in the day, BrailleNote classic and then the MPower, the Orbit 20, and my Humanware NLS E-reader. I never had issues with bad dots on any of those others, but on both of the Focus displays this has happened. I've tried taking an alcohol pad to the display to clean it, but still, it didn't solve anything. I really want to get more use out of this display, as the things aren't cheap, but I don't have the money to send it in for repairs. So, any tips would be appreciated.