dirty heads?

Its holiday time again so I dusted down my trusty (!) pc100 dv camcorder and bought a couple of new tapes (sony).

I always lay down an initial time code on the entire tape before I use them so there is a consistent time code when I come to editing on my PC.

Anyway I left it recording a blnak scree nand when I came back it didn't seem to have laid down a time code. Or picture.

So I record with the cam pointing out the window. nothing.

i put an old used tape into the machine. It plays for about a second and then pixelates and then freezes. The tapes does not look crumpled.

I am assuming this is clogged heads although they look fine.

can I clean these myself or do I have to send them off?