1993 excella 34 ft window seals

Hi all just picked up my 1993 excella 34 ft, and noticed some minor dripping from the push out style windows. The foam seals look like pumice stones and are completely dried out. This seal is on the window frame, and when it's closed, the foam is compressed against the trailer . I am looking for the proper replacement seals for these windows. I would appreciate ANY suggestions. Thinking rubber seals would offe a better sealing surface, but figured I'd ask the experts. Thanks every one!!