Topic: Black sticky-tack
I have found black sticky-tack to be very useful in filming as it is easier to hide that bright blue sticky-tack.
Unfortunately on one makes it, so I made some myself !
All you do is take some sticky-tack and squish it out flat in a table, then you colour it black with a sharpie, kneed it in and repeat until it is black throughout.
Let me know if this helps.
-Gospelnut