The B&S owner manual and service manual both say you should regularly wash the foam element with liquid detergent and water, squeeze it dry, saturate it with engine oil, and squeeze most of the oil back out of it leaving it damp with oil.
I've found that filter elements that have been treated this way for twenty-five years or more are likely to fall apart, but it only takes ten minutes to cut a new one out of a car-washing sponge.
