Range on Key fob much less?

Not really an answer here, but another person with a similar situation -- with my Subaru Outback (2002) key fob. In the case of mine, the key fob was once upon a time dunked in salt water. I've done everything I can think of to rinse it clean of residual salt. I've suspected that the problem is due to poor battery contacts (due to oxidation/corrosion). Usually when I have I cleaned the contacts with #600 sand paper the key fob comes back to life. But this cleaning of the contacts seems less effective each time ... despite battery replacement. Any ideas would be welcome.

Steve Hankin
March 2008