Scratch

No, I don't think so. You would probably have to do it manually by opening the variables section SCRATCH and hitting 'Delete a variable'.

Form what I've seen, SCRATCH seems to only automatically delete unused broadcast messages, and variables that I've attempted to delete (but forgot to remove in a script) come back when I hit 'Save'.

I'd like to see the automatic deletion for unused variables, it can be helpful in saving time and saving space.

Paddle2See wrote:

While we're at it...let's ask for a variable renaming and scope changing feature!

Hmmmm... Scope changing? I'd Google it, but I fear I'm only going to get results for sniper rifles, telescopes, and binoculars. 

BoltBait wrote:

He's referring to the ability to change a variable from only one sprite to all sprites.

I've had trouble with this scope stuff when dragging a script from one sprite to another.  If it includes any local variables, it doesn't work properly on the second sprite.  I've had to rewrite the block by looking at the newly dragged in script.

I haven't had that trouble...but I have had trouble after importing a sprite with scripts from another project. Try saving the project any time you find the variables aren't working right...that often sorts out the problem.