Read Only FS on USB stick

Hi All, I recently copied some files onto a USB stick, but now, I cannot delete them from the stick as the fs is readonly. I have tried to chmod, but no luck. I have tried to chmod as roo, still no good. Then I remembered that the fstab sometimes mounts removable devices readonly, but the only drives referenced in fstab are the swap, / and /home partitions. Where would I be able to change the permissions for this drive, please? OpenSuse 13.1 Andrew Greig