Data from the 37 μm channel of the Advanced Very High Resolution Radiometer (AVHRR) are contaminated by interference which appears in the images as a herring-bone pattern. This interference has been present, to a greater or lesser extent, in the data from all six of the instruments which have flown to date. A measure of the quality of the imagery, estimated from the NOAA-7 and NOAA-9 instruments’ calibration data, is used to gain an idea of their progressive deterioration over each satellite's lifetime. The spectral properties of the Fourier transform of the data are examined and used to attenuate the unwanted components of the signal to an acceptable level. Two simple restoration algorithms are applied to a particularly severely contaminated NOAA-7 image and the resulting images presented.