Flashdisk : cant see anything but have Something in it ( MAC ) Resetting Mac Flashdisk

My flashdisk
Mac

Te pic up there is my flashdisk that have a lot of things on it but it doesnt show , This is how you handle this kind of situation ( Only on MAC ) :
1) Open disk utility
2) you will see All of your USB, Harddrive and any sort of your stuff
3) click your flashdisk/USB
4) There should be an erase button in top
5) Just click it and then
6) Ur flash disk reset