This is what I used the one year I tried WS. I didn't figure out a way to replace the opaque cover with translucent film (slit for ventilation) for some weeks, and I kept it on a shady porch for many weeks, hoping it would get cold enough to stratify.
It never dried out, but then nothing in it ever sprouted, except the Penstemon that took until April-may for ANY to be visible (barely) to the naked eye.
I have such a small yard, I don't need a whole milk jug-full of any one variety. And, two years later, I've only found a total of 2 milk jubs. (I should look for our local solid waste transfer station and/or dump).
WS attempt above , 2010-2011. There are a few mini-micro- Penstmon sprouts on the left, on vermiculite.
I usually start small seeds in trays, inside, now, but back then I used a lot of Solo cups.