why does it only read the last item ?

I'm not actually sure what you're trying to do here with that clean function.

I assume you meant to do this:

local names = {"LavaSword","test"}
function clean()
    Player.Character.Humanoid:UnequipTools() --forcefully unequips all Tools, so you don't miss any in the loop.
    for i = 1,#names do
            if Player.Backpack:FindFirstChild(names[i],true) then
                Player.Backpack:FindFirstChild(names[i],true):remove()
            end
    end
end

clean()