--- type: restriction id: usps-inks-flammable-or-combustible-liquid asset: shipping-restrictions-by-class title: "Inks (flammable or combustible liquid) — Postal shipping restrictions by item category" sources: - https://pe.usps.com/text/pub52/pub52c3_022.htm source_quote: "Inks: Classified as flammable or combustible liquids. Defined as colored liquids used for writing, drawing, and printing, and often composed of pigments such as carbon black suspended in a drying oil. They are mailable if they qualify as Limited Quantity surface material" generated: true harvested: 2026-08-04 stale_after: 2027-08-04 item_category: "Inks (flammable or combustible liquid)" carrier: "USPS" restriction_type: "restricted" scope: "domestic mail via surface transportation" conditions: "Mailable if qualify as Limited Quantity surface material and meet requirements; primary receptacles must be cushioned with absorbent material; follow Packaging Instruction 3A or 3B as applicable" verified: false unverified_fields: carrier, conditions, item_category, restriction_type --- **Item category:** Inks (flammable or combustible liquid) **Carrier:** USPS **Restriction type:** restricted **Scope:** domestic mail via surface transportation **Conditions:** Mailable if qualify as Limited Quantity surface material and meet requirements; primary receptacles must be cushioned with absorbent material; follow Packaging Instruction 3A or 3B as applicable > Inks: Classified as flammable or combustible liquids. Defined as colored liquids used for writing, drawing, and printing, and often composed of pigments such as carbon black suspended in a drying oil. They are mailable if they qualify as Limited Quantity surface material Source: