Regular burned wood decays within seconds, like, less than 15 seconds, and that's even if you lock it down. This I know from seeing if it was possible to make more of the permanent type (no success). Newbie items decay in what, 90 seconds?
Whoever buys it isn't going to just leave it lying about anyway, they'll lock it down. Even if it decays in the same time it takes a corpse to decay, this is still a good rare item. You can always make new corpses (and lock them down). You can't make this burned wood.
Let's say if it lasts 5 minutes on the ground or floor it's good? Buyer agrees to either keep it safe in their pack, bank box or lock it in their house? Experimenting with long periods of time is at the buyer's own risk. Everything decays at some point.