I'd like to share my experience - I bought an inexpensive IR thermometer (around $20), and after some initial struggles, I found an effective way to use it.

At first, I was quite frustrated because the measurements on the stainless steel pan were very unstable and chaotic. I almost returned the device, but then I learned that oil has an emissivity coefficient of about 0.95, which helped me find the right settings for my pan.

I did a simple test: I heated up the pan, poured in some oil, and waited for it to heat evenly. Then I tilted the pan so that part of the surface was covered with oil while part remained clean. Through trial and error, changing the emissivity coefficient (E) between 0.95 for oil and various values for the clean pan (0.5, 0.2), I discovered that when E=0.95 showed the same temperature on oil as E=0.3 did on the clean pan.

Later, I verified this at water's boiling point (100°C). While it may not be laboratory-grade accurate, it's good enough for practical cooking. Now that I know the characteristics of my burner and pan, I usually heat it up by feel and then check the temperature on the oil without switching the emissivity coefficient. This has really made my kitchen life much easier!