The top photo shows a “bib” I fabricated out of a shower pan liner. I found this material at a home center box store. The material is 40-mil PVC liner, the manufacturer is OATEY, and it comes as a 5×6-foot sheet.
For my bib, I cut a piece that was 20×20 inches. In the center, I cut out a 6-inch circular area so that it would fit around the prop shaft extension on my Van’s RV-6A. Then I cut a slot between the circular opening and the edge of the bib (liner).
To use, I place the bib in the space between the front of the cowling and the back of the spinner. This allows me to remove and install the cowling without scratching the paint on either the front of the cowling or the back of the spinner. The bottom photo shows the bib in place prior to removing the cowling.