I plead guilty to jinxing your mouse. grin Seriously, I'm beginning to think that crud other than oils and stuff on my fingers may be involved. In my area, the pollen and mold spores have been horrendous for the whole summer and I constantly taste the air, have a runny nose, gritty eyes and a tickle in the throat. My cat has to have his eyes cleaned several times a day. I seems to me that that's a factor in gumming up the scroll wheel.

I noticed that, after cleaning the scroll wheel with water, a black film formed around the wheel. It wouldn't come off with water and grudgingly came off with alcohol. There was stuff that looked the same on my car and it wouldn't come off with scrubbing, even in a car wash. In fact, I had to scrape it off my windows. Eventually, enough rain fell to wash it away but it took a lot of time.


Jon

macOS 11.7.10, iMac Retina 5K 27-inch, late 2014, 3.5 GHz Intel Core i5, 1 TB fusion drive, 16 GB RAM, Epson SureColor P600, Photoshop CC, Lightroom CC, MS Office 365