This idea works only for pans that are oven safe. In addition to your Fluke you’ll need one of those digital meat thermometers that have an oven-safe wire on them so you can leave the probe in the oven (with the digital read-out unit OUTSIDE THE OVEN) (for example http://www.homedepot.com/p/Maverick-R… ).
1. Put the pan and digital probe in your oven (probe lying in the pan).
2. Turn on the oven to some favorite pan-cooking temperature, say 375F.
3. Wait until everything heats up – i.e. until the reading on the digital readout stabilizes.
4. Take out the pan and take a reading off its surface with your Fluke. If the Fluke’s reading is lower than that of the digital thermometer, lower the Fluke’s emissivity setting; if higher, increase the setting. Keep adjusting the setting until the Fluke reads the same as the digital thermometer.
5. By the time you get a temperature match things will probably have cooled down some, maybe unevenly (e.g. probe maybe cooling down faster than the pan),so put the pan and probe back in the oven, let them get back up to temperature, then repeat (4) to check / fine tune your emissivity setting.
Record your final emissivity setting. Whenever you want to use your Fluke with that pan, make sure you have it’s emissivity set at that value.
I don’t know how much your cooking oil could affect the overall emissivity (and consequently your Fluke’s accuracy), so just for the hell of it I’d repeat the whole experiment with some oil in the pan, and see what Fluke setting would be best for taking readings off an oily pan.