We recently had our old FHA system replaced with hydronic panels. Now I have a lot of unused floor vent holes in every room in the house. And they have the old grates on them. I'd like to keep the dust and debris from collecting in these old disused vent holes and switch out the grates for solid covers of brass.

But I cannot find any. Do they even exist? Google searches are challenging as they return the same results over and over: places that sell what I already have!

Any leads on what I need?