In the case of 1.5V batteries, most are alcaline so maybe a vinegar solution for cleanup would help ballance out the alcaline P.H.
I've always wanted to try a very small dab of silicon grease, maybe spark plug boot grease if you can get it not too expensively. The heat transfer grease used between electronic components and heat sinks would be good, but is way too expensive. Another issue is whether the particular battery holder provides enough pressure to get through a layer of grease and make good contact. tom
