I have been searching but haven't seen this suggestion yet. There is a thick plastic tape usually used as a anti abrasion cover called helicopter tape. It's clear and easy to work with. I stuck it on the inside surface of both handles. I can feel it when I grab the handle but it's not sticky and is definitely better than touching sharp edges. You've probably seen it before on bicycles as a chain slap guard on the chainstay. It's not cheap usually but it can be repositioned easily if you want to straighten it in the initial application, so there isn't much waste.