A couple of years ago, I rewired a completely gutted Civil War-era house in Richmond's historic Church Hill (remember Patrick Henry's speech?), and the HO wanted a particular 5" recessed lighting can with swivel-eye trim over each fire-place mantle.
Naturally, for whatever reason, the particular can didn't come in an IC-rated version, so I improvised by making simple 1-foot-cube cages using 1/2"-mesh metal-fabric screening for the three upstairs cans to keep the blown-in insulation 3" away.
I made each cage with five sides from a single piece of mesh cut into a cross shape, and the bottom side open to the drywall. The inspector loved the simple and effective design. The mesh allows heat to disperse while keeping the fluff at bay.