A good pump for viscous liquids would be any kind of sewage pump. After all, they're made to pump solid waste, so viscous liquids should be easy.
~Darren Crook
I've been researching this topic myself somewhat, too. I've looked up some possible solutions, and I came up with teflon. A teflon spray applied to any particular area of concern should prevent any degradation of the plastic/rubber, according to my research. The teflon and most of the cheaper...