When measuring objects with lower emissivity such as bronze, copper, aluminum or stainless steel you will need to ether adjust the emissivity setting (if available) or apply a known emissivity value to the object.
Cover the surface to be measured with masking tape or flat black paint (<148 °C/300 °F). Allow time for the tape or paint to reach the same temperature as the surface beneath it. Measure the temperature of the tape or painted surface. With a locked emissivity instrument you now have a stable spot to make future measurements.
If you have an instrument with adjustable emissivity using the above technique can gain you the a closer emissivity % value then a general chart. Set your emissivity to .95 to .98, make the same measurement. Make note of the temperature, now aim off of the tap or paint. Roll the emissivity down till you reach the same temperature you noted before. You now know the emissivity of the new target.