As per post below I have run the cleaning head through enough times that it doesn't seem dirty on an old tape but the tape I used when they were dirty still shows contamination when I try to record over the footage. Can I recontaminate the heads by running the contaminated footage over? Should I trash the bad tape although it is a new one? Why doesn't it rerecord over the contaminated footage? ...Thanks..
I'm having a little trouble following your explaniation of the problem, but if I read your post correctly, it is certainly possible that the bad section you see when you play your tape is not attributed to contamination on the video heads, but instead is a defect in the tape itself. If this is the case, recording over the spot will not correct the error.
I've had a fair share of bad tapes over the years, so it's not entirely uncommon. I'd just trash it and use a new tape. If you discover that these problems are common, use a different brand of media.
Also, T-160 tapes are made with a thinner and less resilient tape, so I'd recommend that you stick with a T-120 or smaller, especially if you record over them repeatedly.