I was thinking the same thing, but would that still allow switching gears easily?

@Vikas That is true. However, at least in every apartment building I've lived in, residents are required to put their trash in large plastic trash bags before putting them in the dumpster. I suppose a compostable trash bag could be used as a solution for this question, so long as it's still waterproof.

I was envisioning that you were at a counter at a restaurant, and you could just get a few paper napkins from the server. But if you're not at a restaurant, you'd either have to bring something with you (sub-optimal for sure!) or find something to use in your current environment.

@user151841 That's mostly true, but surface tension can prevent water from entering a tiny cavity that has air in it. Since mold could be poisonous (and the items are not very expensive) it's not worth the risk.

@Stan The way the question was worded ("I need a way to remember...") really sounds like it requires a mind-hack. I added a note at the bottom that hopefully circumvents the need for a mind-hack, and voted to reopen the question.

@nielsnielsen This question has been reopened. You should post your comment as an answer. Personally, I keep grocery bags in my car ... and if I find myself in the grocery store without them, I run out to the car to retrieve them before checking out. Feel free to add that to your answer.

@Lefty I've always used Ziploc bags, but since that's a brand I avoided mentioning it. Your fabric drawstring bags would be an excellent alternative, especially since you could hang them! For the label, I like the idea of looping a tag around one of the drawstrings rather than applying something to the fabric (which as you already know would be wrinkled and hard to read).