Hoarding plants means also hoarding nursery pots. Keeping some of them is useful for planting other seedlings and plants, as needed. But there's a limit on how many one can keep in storage. Instead of just throwing them away, we can make bonsai training pots out of them. That way they also keep less storage space.
First step is to mark the desired height of the training pot. I use a wider bowl/tray and the bonsai round-table for that. You can also do it more precisely with a ruler - placing several initial marks around the plastic pot.
Using scissors or snips (tin snips in the image above), cut the side of the pot all the way down to the marking. Repeat at several positions around the pot, so that the upper part of the pot is sliced into several "wings" .