The short answer is to keep moisture out of the bin, keep ice from bonding the lid to the rim, and deal with snow around the container before it turns to solid ice. In a city, that usually means a mix of good trash habits and a little preventive maintenance, especially if you share a bin with neighbors.
Start with what goes in the bin. Wet food scraps, loose coffee grounds, snow-covered packaging, and liquids are the main reasons lids freeze shut. Bag food waste tightly, double-bag anything soggy, drain containers before tossing them, and avoid dumping snow or ice into the bin. If your building uses shared wheelie bins, ask neighbors to keep lids closed and not overfill them. A bin that is packed too full keeps the lid slightly open, letting meltwater run into the rim and refreeze.
Next, treat the contact points. Clean the lid rim, hinge, and any latch, then apply a thin layer of food-grade silicone grease, silicone spray, or petroleum jelly to the areas where the lid meets the bin. You do not need a thick coating; a little goes a long way. Cooking spray can work in a pinch, but it wears off faster. Avoid using antifreeze, motor oil, or harsh deicers inside the bin. They can harm pets, waste workers, and the container itself.
A liner helps more than most people expect. Use a heavy-duty trash bag and make sure it folds over the rim without getting pinched in the lid. Some people put a layer of cardboard or newspaper at the bottom to absorb moisture, but replace it as soon as it gets damp. If your bin sits in an alley or on the street, keep it out of snowbanks and away from downspouts. Clear snow and ice from around the lid and base, and if possible raise the bin on bricks or a small pallet so it does not freeze to the ground.
For shared urban bins, report broken lids, missing hinges, and cracks to your landlord or the city. A damaged lid lets in water and makes freezing much more likely. You can also keep a small plastic scraper or rubber mallet nearby. If the lid is frozen, do not kick it or pry it with metal. Gently tap around the rim with a rubber mallet, pour a little warm, not boiling, water along the seam, and wait a minute before opening. Hot water can refreeze quickly and make the problem worse.
The goal is not to keep the bin warm; it is to keep water from pooling and bonding the lid. Dry waste, a lined bin, a lubricated rim, and a clear, snow-free spot will prevent most winter lockups.