If you are talking about the blow-by pipe filter, also known as crankcase ventilation screen, those can be cleaned in a solvent and re-used forever and ever, as long as the filter element is steel-wool or non-synthetic material which might dissolve.
Dip the element in an empty 11 oz coffee can full of gasoline or other solvent for a day or so then pull the filter out and allow to dry, then re-install in the tube assembly.
If the filter was gunked up really bad, it might take longer to dissolve all the gunk, but we are talking 1950's refined oil for the filter to be that bad.