Depends on the plastic. Gets 30 below here and mine don't shatter. They rot if left in the sun during off season.

On plant pots and plastic jugs like Kosio's design if you take a hot soldering iron and melt the end-zone plastic that there is more support before you cut the slot.

Interesting shock springs on your snares Kosoi, care to explain

The cheap plant pots that houseplants come in tend to shatter when it is cold or they are covered in ice, but I used a bunch my wife bought houseplants in because they are free (and her father works at a store with a nursery, so I can get more from him). I didn't care for them because they are shallow, you need to use smaller bait and make sure it is clear at the back of the pot. I tend to use big chunks of bait like a beaver drumstick wired around the bone and hanging lengthwise. I had problems with catching marten by the face, and even caught one with the bait in its mouth. Because they aren't having to go through the trap to get to the bait, they can just stick their head up there and grab it, and are setting the trap off when tugging on the bait. This isn't an insurmountable obstacle, I just needed to change how I attached the bait. They are quick and easy to to put up and set, and you can carry a lot of them on a snowmachine, but I prefer boxes if I have room to carry them.

I used flower pots for many years, mostly because they were light, and stack-able. I had a lot of refusals, and bears tore them down constantly.
Not a big fan.
Boxes are a pain, but catch much better, in my world.

martin box built with wooden board lasts a long time and returns to nature, not plastic!!! more easy to insert trap in stronger and tough.not really plywood fan cause a lot of squirrel and hare,porky....

I don't cut slots. The plastic does not stay out on the line. The sun will kill them and animals will knock them down. Nothing more natural than a bunch of rectangular wooden boxes hanging in the forest year round.

Pretty much sums up my thoughts on what is brought into the set. I leave my boxes out and for the most part the bears and porcupines leave them alone. I do nail them kind of loosely so they don’t make it very interesting for the bears to get them down.

For bait beaver is my go to, if I have it. Deer tallow, herring, jam, leftover ham or steak, carrots even. I honestly don’t think it matters much if the marten are there.