1930's FRAM P-2 Oil Filter

It's best value may well be for a static display engine. There are some horror stories of folks using very old NOS filters only to find the paper element had deteriorated or weakened over time and the first surge of oil turned it into mush that filled and plugged some of the oil galleries, with the expected result.

In addition to the paper filtering substance mentioned above, some filter designs from the 1930's use a cotten thread material as the filtering media. You can imagine the natural breakdown that would occur with that substance over the years, and the bad outcome that could result if the filter was eventually put into service (as noted by Owen_Dyneto above). John