Does anyone remember the title of a 70s movie of a "gang" war between 2 groups of boys. The main thing I remember is that the "treasure" was caulk to hold the glass in a window or door, before it hardens.

It may have been in B/W and with subtitles.

Any pointers are appreciated.

Does anyone know the name of this movie? The plot involved a school for witches. I only remember a few scenes:

* prank of spraying the hallways with (fire extinguisher?) foam, and of bypasing this by swinging from the ceiling bars that supported the walls
* classroom scene where a kid grows a long ...