Macbook osX reporting USB stick full with free space

I was having this problem before and every time it takes me a bit of time to figure out that osX likes to use .Trashes directories to hold trashed files on the volume itself instead of moving them off onto the macbooks own trash folder.

It is irritating as the Finder applications does not show dot (.) files by default and I hate to mess around in a file browser. Next time you encounter this you can try this in your terminal:

$ df -h

Filesystem                Size   Used  Avail Capacity  Mounted on
/dev/disk1s1              984M   970M    14M    99%    /Volumes/USBStick


$ ls -a /Volumes/USBStick

.
..
.DS_Store
.Trashes      <<<< need to dump this.
._.Trashes
BPM Paper


$ rm -rf /Volumes/USBStick/.Trashes


$ df -h
Filesystem                Size   Used  Avail Capacity  Mounted on
/dev/disk1s1              984M    45M   939M     5%    /Volumes/USBStick

This will get you back your free space.