That's an excellent and practical question! For public outdoor bins, the single most secure attachment method is a dedicated, lockable liner retention system. This isn't about a simple bungee cord. We're talking about integrated metal clips or a rigid internal frame that the liner's collar hooks onto, which is then secured with a small built-in lock or a tamper-resistant fastener. This prevents people from easily pulling the entire liner out (theft or vandalism) and helps keep the liner's mouth open for proper use.
Why is this the top choice? Public bins face unique challenges: wind, attempted theft of the liner bag itself, and deliberate mess-making. A locked system directly addresses these. The liner stays firmly in place, reducing spills and litter scatter.
Good alternatives, if a built-in lock isn't possible, are heavy-duty, wide-jaw spring clips or robust plastic cinch straps fastened to the bin's handles or anchors. These must be made of UV-resistant, durable materials. Avoid simple elastic bands or flimsy ties—they degrade quickly and fail.
Ultimately, security combines the right hardware with a properly sized, heavy-gauge liner. The liner should be thick enough to resist tearing but fitted so its collar can be fully engaged with the locking clip or frame. This one-two punch of a robust bag and a locked attachment point is your best defense for a cleaner, more secure public space.