White Cotton Cloth under insert bricks ?

[chrishearth]

I recently got a Vermont Castings Montpellier wood fireplace insert, and I have already been using it quite a bit. I went to clean the ash out of it today, and I took the two slanted bottom bricks out and used my fireplace shovel to scoop ash out, and much to my surprise I mistakenly ended up scooping up a piece of cotton cloth which appears to be affixed to the insert. I looked in my manual, and I haven't been able to find any mention of this, is this cloth supposed to be there, or did the installers forget to remove it before putting it together?
If it is supposed to be there, where might I be able to find a replacement, because I cut it up pretty good when using the shovel to scrape up ash.

I have attached some pictures to better illustrate what I am talking about.

Please help,
Thanks,
-Chris

 

[begreen]

I suspect that is ceramic wool, most likely kaowool. Leave it be.