Best practice is to replace the pot entirely. I ordered in a Dunlop Hot Potz II 100K. This is far more reliable and is sealed well against dust ingress. It's a popular replacement part for a wide variety of wahs on the market.
It was a relatively easy replacement. The original pot was unbolted from its mount to the frame, and then desoldered from its board. Wires were then used to connect the Hot Potz II to the original board, as it does not of a PCB mounting type like the original part. Once the new pot was bolted in place and the rack readjusted to suit, the wah was ready to go again!