We have swan-neck swivel taps in the kitchen and within a couple of weeks, the swivel becomes very tight. I take them apart and administer silicone grease to the O rings and we are ok for another couple of weeks. It strikes me that some form of permanent lubrication would be better and I am wondering if it is possible to obtain self-lubricating O rings, e.g. impregnated with graphite. Would this work and if so where could I obtain such?