The maintenance of the propeller is fundamental for good performance.
The propeller is one of the most important elements to be borne in mind for the pre-flight check list. You must look out for both any possible impacts by objects during any phase of the previous flight and the cleanness of the propeller.
Use a cloth, lightly soaked in soapy water, to remove stains and any remains of insects caught during use and which would noticeably reduce performance.
If the propeller is very stained with oil, you can spray it with an ovencleaner and, once clean, rinse it with water and dry it off with a cloth.
All impacts must be sealed and filled to surface level of the blade with epoxy or (much easier and quicker) with cyanoacrylate and bicarbonate (on the shielding) or cyanoacrylate and powdered wood and bicarbonate on the rest of the surface.
When your spare propeller is not in use, it is advisable to wrap it up and store it horizontally in a dry place which is not subject to excessively high temperatures.
Any important repairs must be carried out with a total guarantee of perfect performance, and ensuring that the picth of both blades is correct and that they are properly balanced.