I had a Industar 22 that had a bunch of cleaning marks. Not quite 'took sandpaper to the lens' but not far off from it.

It did fine at times when stopped down:

http://www.flickr.com/photos/cannelbrae/5044331116

But it also would 'glow' much more than I liked:

http://www.flickr.com/photos/cannelbrae/5044330656

That lens put me off to anything with excessive cleaning marks for general purpose use. Enough scratches causes results similar to a hazy lens. That said, I don't mind how they work with some shots:

http://www.flickr.com/photos/cannelbrae/4800562503

In general, my issue with cleaning marks and haze is that it makes predicting the lenses behavior more of a challenge. It also means that I may not be able to get the look I want in a high contrast situation. Its easier to 'add' this effect with filters if/when the look is desired.