seriously? 38Mb? that's maybe 7 songs... if you're desperate to get a few more songs, check your music library for duplicate songs.
that 38Mb is probably space that is reserved for applications which may need it at some point.
also, i think this is like the 5th topic you've made about this. do you really listen to/watch/look at all 8Gb/16Gb of whatever you have on there? in which case i suggest you just get an ipod classic.