Salvage

Can somebody explain me the use of salvage items ? and that Expert or Superior Salvage Kit ? i have no clue what to do with it please help

A normal salvage kit will salvage common materials from an item.

An expert salvage kit will salvage common and rare materials as well as Runes and insignias from salvage items.

A Superior salvage kit is simply an expert kit with more usages.
A Charr salvage kit (a rare pre-searing item) is an expert kit with 5 uses.

hmm ok thanks

http://wiki.guildwars.com/wiki/Salvage

is a good point of reference as well. You can sell materials/rare materials that you salvage to other players or to the Rare/Material Trader...or save them up for your armor etc

Also it's usually a good idea to trade in your "Battle Commendations" and "Equipment Requisitions" you get from doing quests for superior salvage kits. I think the kits sell for 1k, but if you keep them the 100 uses could be more valuable from all the mods and rare materials you can get from salvaging stuff. I usually salvage all white armor I find and typically get a leather squares and steel ingots.