Here is a little Instructable, for little trash bags, for all your little garbage needs.

The idea and execution of this project is simple and effective as well as a great way to upcycle and reuse grocery bags!

I'm creating an urban alleyway scene and have been collecting lots of miniature additions to add to it. The garbage bags and recycling bags (my city uses blue bags for recycling) add a nice touch of detail and realism.

Very little is needed in the way of supplies...

Supplies

Iron and ironing board

Grocery bags

Parchment paper

Scissors, ruler, pen

Trash to fill your bags!

Step 1: Measure and Cut

I found out its actually really easy to find the sizes of a garbage bag online beyond the gallon measurement you are used to seeing. I didn't expect to find the dimensions for the rectangle shape of an unopened bag, lucky me!

I took the measurements for a kitchen sized trash bag (13 gal) but it ended up being a bit too small for my needs and I ended up going with the 33gal sized bags.

13gal kitchen bag

23.5" x 25" (1:1)

2.35" x 2.5" (1:10)

33gal garbage bags:

33" x 38" (1:1)

3.3" x 3.8" (1:10)

Measure! I took advantage of the bottom of the bag so one side of my rectangle was already accounted for. If you choose to cut anywhere else on the bag you'll need to cut a double length strip and fold it in half.

The edges tend to melt inward a bit so make your bag a little wider to compensate for shrinkage.

Cut! I didn't worry too much about being really precise since you'll be turning it inside out it'll hide a lot of errors.

Step 2: Parchment Paper and Ironing

I have only experimented with grocery bags and they melt pretty predictably. I can't vouch for what thicker, thinner or different type plastics might do.

Parchment paper is the hero of the day for this project to save your iron and ironing board from melted plastic. Don't use wax paper, that'll ruin your iron and ruin your day just as quickly as melted plastic. Make sure you have the plastic enveloped in parchment paper at all times while ironing!

If you have text or graphics you want to have on the outside of your bag, turn them to the inside now as you'll flip the bag inside out after ironing.

Iron the two side lengths. You should only have to iron two sides. Don't forget to leave a top opening!

I had my iron initially set to the highest temperature. This worked just fine but you had to be quick as it melted/dissolved the plastic if you weren't careful. The plastic seams held up well though!

I lowered the temperature for my second bag even though the highest heat worked it felt like overkill. The lower heat (about a 4 out of 6 on my iron) needed a few more passes to ensure a good seal but it felt a bit more controllable. Maybe setting it to 5 would have been the sweet spot....feel free to test on scrap pieces of plastic with your own iron first.

If your edge seal fails, just take it back under the iron and it'll patch right up!

In the third picture you can see the amount of shrinkage from the edge you should expect and compensate for in your measurements. I had the plastic all the way to the edge of the parchment paper and you can see how far it melted inwards from the edge.

Step 3: Flip, Fill, and Tie

Flip the bag inside out to hide any irregularities from melting your edges.

Fill it with trash! For my blue recycling bag I used some extra parchment paper to have it looking a feeling a bit lighter and looking like it was full of plastic. I'm hoping get around to making a bunch of tiny soda cans eventually to fill a recycling bag for real detail. For my trash bag I used fabric scraps to give it a bit more weight and a trashier look. It is a garbage bag after all, fill it with whatever trash you want!

Tie the top into a knotat least once, tie twice (if you have very nimble fingers) for the best appearance.

That's it, simple and quick way to add some detail to an urban miniature scene. Enjoy!