Monovalve preservation(?)

[mattc]

A few months back I went to my local NAPA and asked about a monovalve for my 82 300D. They offered me a (MTC?) for like $10.00 - $15.00. I said I saw one on your web site, and that was the one I wanted! It was a Bosch
1 147 213 007, and they had it the next day. It was $104.00.
After reading around on here, and noticing they are getting rare, I decided to get a spare. I picked up another one today. Both the boxes looked a little battered... ...not smashed, but more like they had been moved around on the shelf a bunch of times.
My question is: Seeing as these are of undetermined age, and I plan on holding on to it for "who knows how long", would anyone consider slathering it in 100% silicone grease, and putting it in a plastic zip-lock, and putting it back in the box - to preserve it?
Any other suggestions for extending the shelf life of the rubber components on this thing would be taken into consideration - and appreciated. Thanks, Matt