(Based on a few G.D. Practices and Techniques, plus the ancestral practices of African witch-doctors and medicine-men).
Charms, talismans, potions and such things very often depend on the faith and imagination of the user for their powers.
The stronger the faith and hope and imagination of the user in the efficacy of the charm or talisman, the more effective it will be.
Be sure, then, that your faith is very, very strong and your hope infallible when making or using charms, or when preparing them for others.
But there are very few exceptions to the general rule that charms depend on faith and confidence reposed in then. 
Those few exceptions concern some rare charms and talismans which act-by themselves, irrespective of the belief of the user.
Nobody, no matter how powerful, can affect you with any charms at a distance; it is his telepathic message or telepathic hypnotism that may reach one and harm or influence one through the subconscious processes.
As long as you are very bold and fearless about these things they cannot affect you.
Fear is the main killer.
Below then we give a few formulas which you can make or duplicate…
To bind thieves, destroy evil charms and render an enemy’s charms useless: get some menstrual blood of a virgin and, with a white cotton-wool apply it to the doors of your house or room, or to the suspected place. 
This is also the most powerful form of self-protection from charms and spells.
But note the word, virgin, consecrated olive oil will also serve in some cases.
How To Construct Powerful Talisman, Charms And Potions
