We routinely boil the stainless steel portions of our turret, bead blocks, ion source lens, and filament beads in ACS-grade hydrogen peroxide to effectively remove Re buildup (no scrubbing of slit plates or filing of used filament beads needed!) and oxidize residual organics. The method is described in Mass Spectrometry Guidebook .
After a periodic cleaning and reassembly of a full turret and hats, we will also load a set of outgassed Re centers into the blocks and run each one up to 4A for 30 minutes in the mass spec (an overnight automated process) to heat the block and hats up; we find that this mitigates the magnitude of isobaric interferences on mass 204 (and other isotopes to lesser degree) which are usually more intense on the first turret post-cleaning.