Ball Canning Jars: Use them over and over? A simple question:

Can I seal and reseal Ball canning jars over and over?  How long before the seal gets busted usually?

Also, how do you clean the rubber seal ring without damaging it?
Sure you can use the jars over and over, but the lids should never be reused.  That rubber seal is damaged the first time you use it.  They are designed to soften during the canning process in order to form an air-tight seal.  They may not form that seal upon reuse.  You should always use new lids when canning.