Why don't u give sdelete a try? I haven't used it, but it looks like it'll do the job. You can always test it by using an unerase program and then using this utility and running the unerase program again. Compare your results.
BTW: This site has a bunch of cool freeware tools. Take a look around while you are there.
---I asked for safe because I once downloaded a program that said it would rewrite over free space and it deleted the directory it was downloaded in(program files) I also had downloaded a few to test and compare and couldn't remember which was which.