Next time you eat at one of the places that offer the foil sealed moist towels take and extra one and put in your bike pouch. This way after to fix the flat you can clean your hands. Do not litter.
Practice is best. I can pull wheel, pull tire and tube. Find hole in tube and mark. Check inside of tire for object still stuck in there. Then fit new tube, reinstall wheel, pump up. I then stow the old tube, repack the bag and pump. Then I clean my hands. This takes maybe 5 minutes.
Rod