I smoked this hash once and it was worse than soap bar. It looked like something that had been scraped out of the bottom of a public toilet, it wouldn't crumble properly and gave off blue smoke. Apart from this, the hash usually isn't too bad, it's still soap bar but it's pretty clean and actually gets you high. It depends who you get it from.
I've heard they put all kinds of crazy stuff in hash like rubber, shoe polish, coffee grounds, wood varnish.