With regard to what you have mentioned about urinating on an old pickaxe that has been heated with fire in order to undo witchcraft, this is a myth which it is not befitting for a monotheist to believe. We have looked at the site which you referred to, and we saw the one who told you that this action is permissible, but he did not attribute it to any scholar among the early generation, rather he attributed it to Ibn al-Qayyim (may Allah have mercy on him). We looked for a place in which Ibn al-Qayyim stated that it was permissible, and we could not find it. We do not think that it can be proven to be from him or from any other early scholar; rather it is more likely to be an action of the charlatans.
And Allah knows best.