Hello
in France you will often see in the sound man's handy bag a roll of that paste we call "pâte américaine", actually a sealing synthetic rubber.
the pic is the bulk version of it.
We use it mainly to stick a planted mike in a corner (very often in cars), because it is very easy to shape and unstick, and does not leave any residue.
Now I wonder if you guys are actually using this kind of stuff, since we don't have a clue how to call it in english on set!!
Thanks
Fred
(American sound recordists I did the boom for in the past did not use it. Here it started about 15 to 20 years ago I think...)