Originally Posted by
Koyote
As you note, the dried sealant that I find inside my old tires is practically weightless -- as would be obvious to anyone with a moment's thought, since the main ingredients in sealant are liquid, and they evaporate.
Maybe not weightless, but most of the sealant is water and does evaporate. I at some point in the past did weight a tire before and after scraping off the build up of what was pretty much the life of the tire. I don't recall the exact weight, but as you suggest it was surprisngly little.