I have 4 lighters that were in the box of ww2 items from my Grandfather. There is 1 black 1943 zippo lighter that was never used. 2 lighters that I think are British (have a seal stating Ministry of Finance) never used, and 1 lighter that you extinguish the wick by pulling it through the side of the lighter (it has been used). Any thoughts as to what they are worth?