# Inks (flammable or combustible liquid) — Postal shipping restrictions by item category

For Inks (flammable or combustible liquid), carrier is USPS; restriction type is restricted; scope is domestic mail via surface transportation; conditions is 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, recorded from its source on 2026-08-04.

- **Item category:** Inks (flammable or combustible liquid) _(unconfirmed — we could not tie this to the quote below)_
- **Carrier:** USPS _(our reading, not quoted from the source)_
- **Restriction type:** restricted _(our reading, not quoted from the source)_
- **Scope:** domestic mail via surface transportation _(our reading, not quoted from the source)_
- **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 _(unconfirmed — we could not tie this to the quote below)_

## What the source says

> 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

- https://pe.usps.com/text/pub52/pub52c3_022.htm

Last verified: 2026-08-04. Review by: 2027-08-04.
Part of [Postal shipping restrictions by item category](https://referencesource.org/shipping-restrictions-by-class/).