What's the best product to get the gunk out of my shower drain?

I decided to open up my drain last night in my shower and I was completely disgusted by what I found. For some reason the drain is made out of PVC (is that normal? I always thought they would be metal) and it was coated in a layer of gunk that made me sick to my stomach. I reached in with paper towels and got as much of it off as I could but my fingers could only get in a few inches. What's the best product I can use to coat the sides of the drain in a thick cleaning goo and then wash it all away? Will Drano or such things stick to the sides to get it clean or will it just wash right down the drain? It's not clogged, the water flows down it just fine, it's just nasty and now that I know what it looks like I want to get it cleaned.