158.7—Allowance for reduction or loss of merchandise by a natural force or by leakage.
Merchandise subject to ad valorem, specific, or compound rates of duty found at the time of importation to be reduced or diminished by a natural force, such as evaporation, or by leakage, shall be appraised in its condition as imported, with an allowance made in the value, weight, quantity, or measure to the extent of the reduction or loss, except when forbidden by law or regulation.