We have found that the most efficient and effective way to clean Savillex teflon (particularly capsules for zircon dissolution) is to alternate concentrated HF (220°C) and concentrated HCl (180°C), 48 hours each for numerous iterations. This appears to “pump” trace metals out of the resin much more effectively than other more dilute acid treatments. For example, capsules cleaned for several months with alternating HF and 6M HCl which consistently yielded 2-3 pg Pb blanks, when exposed to this new method liberated pulses of tens of pg’s of Pb after each HF step, and now yield capsule blanks indistinguishable from loading blanks (0.2 pg Pb).