Invisible files

I have a sansa e260 and Ive added music files that I now want to remove. I deleted them once from the music folder, but they keep turning up whenever Im playing songs with ‘bad track’. Some files even play even though I thought I removed them??

How do I get rid of these files once and for all?

Format the memory. This will remove all content, but not firmware or any operating files. If you have a v2 version, you’ll have a convenient Format function in the Settings menu.