Poisonraven, that may be your opinion as to the best way to create an "authentic talisman", but for others there are any number of different ways to go about it depending on their path and their personal beliefs and experience.
Personally I work with runic talismans that I make by burning the symbol into a wooden disc and then consecrating it with the four Elements.
Salt is a very ancient ingredient in almost all magical purification rituals across cultures, as is the running water you mentioned. So purifying a talisman with salt is very common and a very old method.
The use of crystals in charging something is far more modern and linked to many New Age practices. Not that it won't work, but it isn't truly ancient. One can create an authentic talisman without the aid of crystals at all.
As a final note, you mention that your method is for creating talismans for "black magic". Truly magic has no color. There is no black or white magic. Magic is simply energy that we harness to do our bidding. Think of it like electricity. Electricity, like magic, is energy; yet we do not talk about "black" or "white" electricity. Same with magic. The only thing which is different is the intent of the caster. This is why the old saying is that a Witch who cannot curse cannot heal. That's because it's the same energy used in either case. The only thing which is different is what the person casting the spell does with it.