Thanks for the suggestion of WD40 and a hair dryer. I've had the light for about ten years and used it so infrequently, that the batteries never failed. So I didn't remember how to open it. Anyway, using the oil and hair dryer, I got it open, but the batteries had NOT leaked! In fact, they were the batteries supplied by Cateye! Anyway, I tried using a butter knife to pry it open and finally learned (or remembered) that you push the top toward the back of the light to remove it.