What's that spot on my tang?

[jesterns2]

I noticed two abnormal spots on my tang and was wondering if anyone could assist me in identification of the spots. The end of the video will give a better look. Thanks in advance!

https://www.youtube.com/watch?v=Zkd4z6deEyo&feature=youtube_gdata_player

 

[Yinzer]

Is he rubbing on rocks?

 

[jesterns2]

I haven't noticed that occurring

 

[Yinzer]

Hmm. I don't have any idea. The video was kind I hard to see until the end. It's both sides right?

 

[jesterns2]

That's correct. The spots seem to be going away.