This nifty shock fork cutaway was up on display in the Specialized booth @ Sea Otter. It's confidence inspiring to see a company that is proud of their product's internal design. It indicates they put some brains behind the function as well as the obviously visible form.
The reason I'm posting this picture is to highlight the yellow foam inner seal. While it may not be standard practice, or suggested by suspension manufacturers, I always store my MTB upside down (easily done if you hang it from hooks in the garage). This soaks the seal with oil and keeps it swollen, retaining oil and keeping out debris. I once met a mechanic who would oil the outer seal after every wash, for more or less the same effect. How much oil got down there, I don't know. However, it seems intuitive that you would want oil leaking out from the inside and not seeping in from the outside to keep the internals debris free (as long as you replace the oil at the suggested maintenance interval).