Watch running fast? The solution may not require a trip to your watchmaker, rather just a demagnetizer.
The “pass-through” style of demagnetizer (this with an opening of 1.5″ x 3″) generally receives much higher quality marks than the inexpensive “ETIC” style more commonly seen in knockoffs (under $15…so you get what you pay for), and in addition to watches can be used for small tools such as tweezers and screwdrivers.
This demagnetizer (note the Amazon product shows as K&D but it is not specifically listed as such) will run hot, requires 120v, and has 300 watts of power. If the recommendation is to be believed due to the heat generated, you run in a single cycle of 5 seconds on followed by 3 minutes off, or three 5-second cycles on and 10 minutes off. I don’t have experience with this device, but wish I had it instead of needing to make a trip to the watchmaker after an associate at an unnamed luxury retail store presented me a tray with different straps from which to select. And the base of the tray was…wait for it…one big magnet.