Hello, I am new here but would like to ask about the vent pipe in my house,[copper] Moved here 3 years ago and allways had trouble flushing toilet. Finall I decided to take out all copper drains then I found this 3inch. vent pipe FULL of green stuff, no wonder would not flush. About 5feet was full and very heavey to lift. Can someone tell me what this is? And also I took some of 1 1/2 inch and some good pipe put on a wood lath to spin and clean it up, I like to make things. But I got real sick,noise running BAD, chest hurt,hard to breath, is this from the corrosion also?? Thanks, With new pipes toilet woks good now.