How long should you run the tape? The best guide is to follow the instructions that come the tape.
The standard practice is to run it between 10 and 15 seconds. Run the tape once for that duration and test your video playback. If the picture still turns up blocky, you can make another two attempts.
When you’re using the tape for the second or third time, remember not to rewind the tape before running it. Please note that you would have to wait until the tape reaches its end before you could rewind it.
The golden rule to remember is running the tape longer doesn’t mean a cleaner camera head. Treat a cleaning tape like a `sand paper’. Prolonged use may damage recording head.
If your problem doesn’t resolve after three tries, you ought to consider sending it to the service centre. Don’t keep on running the cleaning tape, hoping it would resolve your problem.