Product review (5 stars): They wash up fine and were still usable
This is the second set I've bought; the first set was used well over a year.  I use my oven quite a bit, and the guards were stained and brown from the heat.  They wash up fine and were still usable, but the price for a new set of 18" guards was hard to beat.  Please note--the purpose of these rack guards is to help keep your arm/hand from getting burned; these are not oven mitts.  So, yes, if you try to pull out the rack via the guard, you will feel the heat on the rack. Common sense should tell you not to do that.  I would recommend and would buy these again.