The calibration of the balance should be checked weekly with the 100mg calibration weigh which should stabilize at precisely 100mg, and occasionally with the 50g weight using the calibrate procedure. You may have to press it several times to obtain a stable reading of 0.0000g. Open the door, remove the cup with tweezers, and place it in the upright holder. Add sample carefully with the spatula, being careful that no sample is spilled on or adheres to the exterior surface of the cup. You can avoid spilling sample by always gently tapping the spatula on the sample bottle prior to transferring it to the tin cup.
Several transfers are usually necessary to get the required weight.
Transfer the cup and sample back to the balance, close the door, and allow the balance to fully stabilize on the weight. Remove the cup with the flat tweezers, crimp it, fold it over once, and roll it into a round ball. The ball must fall easily into the sample tray. By comparing the new average with the last average you can determine the stability of the instrument. Sequential blanks are not necessary and only waste instrument columns.