"SECTION 135. Petroleum Products Sold to International Carriers and Exempt Entities or Agencies. - Petroleum products sold to the following are exempt from excise tax:

"(a) International carriers of Philippine or foreign registry on their use or consumption outside the Philippines: Provided, That the petroleum products sold to these international carriers shall be stored in a bonded storage tank and may be disposed of only in accordance with the rules and regulations to be prescribed by the Secretary of Finance, upon recommendation of the Commissioner;

"(b) Exempt entities or agencies covered by tax treaties, conventions and other international agreements for their use or consumption: Provided, however, That the country of said foreign international carrier or exempt entities or agencies exempts from similar taxes petroleum products sold to Philippine carriers, entities or agencies; and

"(c) Entities which are by law exempt from direct and indirect taxes.

"SECTION 136. Denaturation, Withdrawal and Use of Denatured Alcohol. - Any person who produces, withdraws, sells, transports or knowingly uses, or is in possession of denatured alcohol, or articles containing denatured alcohol in violation of laws or regulations now or hereafter in force pertaining thereto shall be required to pay the corresponding tax, in addition to the penalties provided for under Title X of this Code.

"SECTION 137. Removal of Spirits Under Bond for Rectification. - Spirits requiring rectification may be removed from the place of production to another establishment for the purpose of rectification without the prepayment of the excise tax: Provided, That the distiller removing such spirits and the rectifier receiving them shall file with the Commissioner their joint bond conditioned upon the payment by the rectifier of the excise tax due on the rectified alcohol: Provided, further, That in cases where alcohol has already been rectified either by original and continuous distillation or by redistillation, no loss for rectification and handling shall be allowed and the rectifier thereof shall pay the excise tax due on such losses: Provided, finally, That where a rectifier makes use of spirits upon which the excise tax has not been paid, he shall be liable for the payment of the tax otherwise due thereon.