True they are one use only. But I would like to know if there is a website or a link to chart what grade of items are returned from what missions. For example Treasure Hunting 340 missions return Grade 6 items. and 300 missions return grade 5, and 240 return Grade 4.
BUT< The problem is when u get to 240, 200, 175, 150, 115 etc. The returns are mixed!