That's a great question, and one that city planners and public works departments think about a lot. Yes, there are definitely designs and materials that make trash cans particularly difficult to graffiti effectively.
The most common strategy is using surfaces that graffiti doesn't adhere to well. Many modern urban bins are made from coated metals or special plastics with a non-porous, smooth finish. When spray paint hits this surface, it struggles to bond properly and often remains wet and smeary for a long time, making the graffiti look messy and ineffective from the start. More importantly, a quick wipe with a rag and some solvent can usually remove it entirely, which discourages vandals who want a permanent mark.
Another approach is using textured or patterned materials. Deeply embossed patterns, perforated metal, or heavily textured surfaces break up the smooth canvas that graffiti artists prefer. It makes clean lines and detailed work nearly impossible, resulting in blurry, unimpressive tags that aren't worth the effort.
Some cities also employ a "sacrificial coating" system. The bin is coated with a clear, anti-graffiti film. If it gets tagged, maintenance crews don't scrub the bin itself; they simply peel off the top layer of film, revealing a fresh, clean surface underneath. It's a very fast and cost-effective cleanup solution.
Finally, the placement and design matter. Installing bins in well-lit, highly visible areas with natural surveillance is a deterrent. Some designs are also simply less appealing targets—sleek, minimalist bins that are seen as integrated urban furniture rather than blank canvases.
So, while no trash can is completely "graffiti-proof," the combination of smart material science, easy maintenance strategies, and thoughtful design creates ones that are particularly difficult and unsatisfying to vandalize, helping keep our public spaces cleaner.