I pour an inch or two of diesel fuel in a small plastic pail and dip a rag into the diesel when I clean the old grease and caked-on dirt from around the zerks and pivot points on my FEL. Not my favorite chore, but I do clean all the crud that builds up 3-4 times each year.
Both Everything Attachments and Agri Supply sell replacement wheels for Cultipackers. Sweet Tractors sells replacement wooden bearings for various cultipackers and, on occasion, sell used cultipacker wheels