I’ve met a lot of Witch’s from numerous backgrounds who have only ever used black thread as a means of keeping things out (black being a color for banishing negativity and numerous other bad spirits and mojo)
After listening to one friend describe how she used black string as a banishing agent for her windows WITHOUT first cleansing her house, it occurred to me how many of us don’t think about it keep bad things IN.
In short, I’ve started using it on curse objects and anything I use to absorb bad luck or anything of the like. For instance, if you are burying a box at the crossroads, tie it up in black thread to keep the bad or good inside and keep anything else out. You can even tie off your box of Witchy things with black string or thread to keep the good in ad the bad out. Or if you curse a poppet for future use and need to keep it in your witch box wrap it up in thread to keep it from tainting everything else in your box :)
Just a thought is all. :)