If you have to store your tools in an area where there is moisture. Maybe a damp shed or garage try putting a few mothballs or moisture retaining crystals in the tool box to absorb the moisture.

You can easily clean rusty tools by rubbing them with a soap filled steel wool pad (brillo pad). Dip the pad in turpentine and rub the tool.

You can prevent small garden tool from rusting by storing them in a bucket of dry sand.

I tend to brush used engine oil onto most of my garden machinery and tools before putting them away for the winter