[labatt]

I would actually replace the mast lights and keep the ones that are installed as spares. Remove the spreader boots, check for corrosion around where the standing rigging goes through the spreaders, and replace the boots if necessary. I used the Edson leather boots - they are not cheap, but are a lot nicer than the current alternatives on the market. If your mast is keel stepped, you may want to look at the shape of the mast boot and look at some of the products on the market in that area. Inspect the mast for any signs of paint flaking as this may be a lead-in to corrosion. Also look at attachment points of dissimilar metals for possible corrosion. Dohenyboy covered most of the other areas already.