FAR 121.629(b):
(b) No person may take off an aircraft when frost, ice, or snow is adhering
to the wings, control surfaces, propellers, engine inlets, or other critical
surfaces of the aircraft or when the takeoff would not be in compliance with
paragraph (c) of this section. Takeoffs with frost under the wing in the area
of the fuel tanks may be authorized by the Administrator.
As Piltdown said, authorization as in the last sentence would be in your FHB, FOM, or similar document. Note that the document would have to be one approved by the FAA, not just a company policy document.