FilterLogic CFL650M Silicone Grease/Lubricant for Coffee Machines. Lubricating o-rings and gaskets during such cleaning processes enables the parts to re-fit and locate as intended (i.e. reducing o-ring roll) and it reduces the friction where surfaces compress, greatly extending the life of such parts and preventing 'cracks' in the seals from occurring (which can be potentially very damaging to your machine depending on the location).
eBay