Allan,
Find that file with the .db extension that you want to delete.
Make sure it is the one you want to delete (usually based on the name).
Instead of Deleting it:
It might be better to move it (Copy / Paste) to a temporary "Brain Files" folder or somewhere you could retrieve it in case you accidentally got rid of the wrong file.
By "Figures" do you mean characters or jpg's of clothing? They are different.
There are Head only, Torso and Full Body avatars or characters that can work with Hal.
The head characters are easily made by an older program called People Putty. It only works well on XP machines and I don't think you can get it from Haptek any more. If you want a variety of characters / heads, etc. you can certainly get and use them with Hal.
There are some to be found at the Virtual Humans Forum and at the AI Dreams Forum, as well as here within this site!
Search for Skins or Characters, etc.