I used full soda bottles for my arm exercises. The bottles felt smooth and one dropped, spilling water everywhere. I now wrap them in towels for a firm grip. This trick keeps my exercise space dry and safe.
Seriously, @kellyw19, if a folded towel throws your form off that bad, wait until you hear about this wild new thing called... wearing lifting gloves. Or maybe even just having slightly sweaty hands. The bulk has never made me miss a lift, but overthinking it sure could.