Short answer: yes, they can be engraved with a city seal, but in most cities it is not as simple as taking a trash can to an engraver. If the can is city property, the seal is usually treated as an official municipal mark, so the work generally needs permission from the department that owns or maintains the can—often public works, sanitation, parks, or downtown management. Some cities have brand rules for public furniture, and official seals may be protected by local code or policy, so you should not copy or engrave one without checking first.
From a technical point of view, urban trash can engraving is very possible. Metal cans can be laser-engraved, etched, or fitted with a cast metal plaque. Plastic cans are usually better suited to molded badges, durable decals, or replaceable panels rather than deep engraving, because carved plastic can collect dirt and wear poorly. Concrete cans can be etched or fitted with a plaque. The most practical approach for many cities is not to engrave the can body directly, but to add a durable, replaceable city seal plaque or molded emblem. That makes maintenance easier if the can is damaged, repainted, or removed.
The bigger issues are cost, visibility, and long-term care. A city seal on trash cans can look official and reinforce civic identity, but it also has to survive cleaning, weather, graffiti removal, and daily public use. Fine engraving may be hard to read and expensive to repair. A simple, high-contrast plaque or molded badge is often better for municipal trash can design. It also helps with public furniture branding without weakening the can structure.
So, if you are asking as a resident, artist, or business owner: yes, it is technically feasible, but you should contact the city first and ask about city seal permission, approved materials, and installation methods. If you are asking as a city official, the best route is usually a small pilot project using durable plaques or molded emblems, with clear approval from the department responsible for the cans. In short, city seal on trash cans is allowed in some places—but only when the city controls the design, permissions, and maintenance plan.