When a commodity not in a container is of such composition or form that it is impossible or impracticable to place a marking on or attach a tag or label to such commodity, a sales slip containing all the information required to be furnished by this Part shall be delivered to the purchaser at the time of the sale and in such case no other marking will be required. Such a sales slip shall be entirely clear and equal to printing in legibility.
N.Y. Comp. Codes R. & Regs. Tit. 1 § 221.15