Three questions...
 

First : How do you "black" your tape? What exactly do you do to the camcorder to black your tape?

Second : I was reusing a tape that had already been recorded on before and I noticed that there were some glitches in my footage. Is this because I was recording over something or could it be dirty heads?

Thrid : What brand head cleaning cassette should I buy? I'm using a Sony trv950 and I always use Sony tapes. And how often should I clean them?

Thanks.

First: "Blacking", or "striping", a tape is nothing more than recording blackness from end to end generally as a prophylactic measure against time code breaks. It's a waste of head and tape wear. With just a bit of thoughtfulness and diligence even a rank amateur can avoid time code breaks. Don't bother.

Second: Impossible to say. Any opinion would be empty speculation.

Third: Brand makes no difference whatsoever. They're all basically the same. Use them sparingly, which means when you start to see break-up in your images and/or when you change brands of tape (hopefully rarely). Just be sure you use the cleaning tape exactly as directed on the packaging.

Thanks Ken.