No tools or fluids method, takes about a minute or two all total:
Unscrew or unclick the retaining plate on the bottom, remove the ball, then find the two or three rollers. Scratch off the accretion on each roller with your sideways fingernail, (so the roller cannot turn more than a few degrees), turning as needed to get all 360 degrees. The lint-like stuff tends to come off in short strands. (The ball is virtually never significantly dirty, leave it be.) Shake the resulting detritus out of the mouse, then pop the ball back in and put on the plate.
(Alcohol dries out rubber and plastic, and it's pointless to sterilize a mouse ball. The mouse ball is like a tire, it picks up lint and moisture by design.)