Please help!

I have a ’99f-150 that has a starter corrosion problem. I replaced the starter last year, and it worked fine, but after parking it last summer for more than a few weeks, the starter connections rusted and needed to be cleaned. This happend three times last summer.

The truck was then run all winter without problems-until I tried to start it today after sitting for three weeks. Can I do anything to stop this from happening, as I don’t use this truck much in the summer?

Many Thanks.