a photo of the inside of my enclosure. Along the back edge are dozens of little rolls of filament "poop" from my printer that didn't end up in the poop ...bucket that is sitting beside it. the inside of the enclosure is lined with butyl rubber soundproofing which has a layer of aluminum on the side pointing in.
https://cdn.masto.host/connectifiedcom/media_attachments/files/112/072/306/837/456/223/original/1b00a157527dbf3e.jpeg