EDIT: Managed to answer own question - see second post!
Thinking I would make a tiny musical instrument, I bought a pack of these:
10pcs DIY DC 5V 6V DC Electromagnet Push Small Inhaled Miniature Solenoid
Features :
[For] 5-6V voltage
[Current] about 350mA
I tried several at both 5v and up to 9v, even with the polarity reversed.
I know some solenoids push and some pull. And generally, you connect it to power and it does one or the other. Well, these draw current but does nothing else!
I did find that if you pull the plunger about halfway out, there's a very small point at which it doesn't fall right out or suck itself back in due to magnetism. If you then connect the power, it sucks itself back in, which seems to be rather wrong for a push type solenoid!
I found these all over the internet, but never any instructions. Am I missing a method of "driving" these properly?