Questions about items i salvaged....

I am running Warrior/Monk. I have been using salvage kit to salvage items that i picked up in battle field and they turned out to be like Granite Slabs, Bones, Wood Blanks etc. My questions is that what can i do with these materials? I don't see Crafter requests these to craft an Armor, they usually ask for Iron and steel or Fur etc. I am getting more and more of these but don't see much use of them? Should i sell the original items picked from field instead of salvage them to be Granite Slabs, Bones, Wood planks again?

When should i use Expert salvage kit ? The kit is very expensive.

Thanks.

Some of the Crefting materials are used for making weapons. Others are used to make rare crafting materials such as parchment and coal.

I personally use expert kits all the time. If I have two kits it is possible to click the regular one on a rare item and lose the rune it holds. If you want to use both use the expert on items that unlock skills, normally purple and gold items. Anything that is highly salvagable will produce more items with an expert kit.

Sell them to the Material trader if you dont want them.
You get more money per 10 of X(cloth, hide, feather, iron, wood, granite) than selling them to a merchant. Collect them to get some cash if anything.