These are heavy duty plastic bags that are very large. I'd never waste these on trash, they have too many other uses! When we go camping they hold gear and keep it waterproof, they make nice "under the bed" storage bags for cloths you hope you will be able to wear again someday etc... If this size is too large you can roll the top or cut it off. Cable ties make nice closures for long term storage. Another use is as a rain poncho. It's amazing how useful plastic of this durability can be around the house or garage. They make very nice dust covers for equipment or machines you can trim to fit, and will hold a backpack that is full of gear. I recently learned that dust is what makes your backpack material stiff as it ages, so I'm hoping these will keep our modern sacks pliable longer than they would otherwise be in the garage.If you do use these for trash, they are strong enough to hold a good load of trash without the usual breaks and tears from the stuff you get at the supermarket. Its the 3 Mil specification that ensures this, its a measure of thickness. Supermarket bags range from three quarters of a Mil to 1.5 Mils, and of course are a lot cheaper and usually smaller, sometimes with closure ties. A 42 Gallon bag can get very heavy if full of leaves. Imagine a 50 gallon drum to estimate what the weight could be when full and you won't be far off. Keep a supply of cable ties handy to close these bags.