Mines never gone away, 10 years now.

I usually keep a small plastic cup handy.
I fold (2) sheets of toilet tissue, and place them over the centre of the cup. I do this4 times to form a Star with the toilet paper, then press another cup into the first cup to make a liner out of toilet paper, in the first ( bottom ) cup. See attached.

Next I have a small Spray Bottle, and I spray around the top of the cup and toilet paper, wet it, then form the wet upper paper around the inside, and let it dry. I always keep 4 made up like this on hand.

After a day, that water dries and left a paper mache liner. I can then use the cup, for a day. Take the liner out each day and flush it, and make up anew one and leave that one to dry out again.

I can spit out the mucous, and I just leave the cup somewhere obscure, in the living room that I can get access to easily.

I actually use 2 cups inside each other for the mould, 2 cups inside each other to squash the paper down with, and hardly any water.

The used ones then flush easily, to get rid of.