Secrets of the sink

I live in a new home, just under a year old. One of the benefits of a newly built home is that it is covered by a warranty, and everything is free to be fixed, you just have to call it in. Of course, after the year is up, you are pretty much on your own. So, I went through the house recently and listed every possible thing that I could think of and called Dave, our home repair guy.

The first thing on our list - the guest room sink. It's my son's bathroom and has been leaking for sometime, unbeknownst to me. I had noticed that the toilet paper he used often had a funny color to it, but I honestly thought that it was due to poor aim by him. I don't use the bathroom, so I let it go without investigation. Come to find out, the sink gushed water everytime he put the faucet on high. We store the extra rolls under the sink and they had been dripped on and then leached the color from the woodwork.

The plumbers came out to fix the sink. They decide I needed a new one, and had to take out the old one. I'm in the other room, reading a book, enjoying the first day back to school after break. I hear "Ma'am, could you look at this please? This is a child's bathroom isn't it?" My head races to try to figure out what could be down that drain to make him ask me this. I look over his shoulder, seeing just the pipe with water in it.

"What, what is it, I don't see anything"
"Ma'am, why is this water black?"
"I guess it is, isn't it."

Think, think, think. What has gone down this drain, what could have possible made it black? Then it hits me. My dear son had been painting a few days back and had decided to make a finger painting. It's just the paint washed down the drain. Whew, nothing dangerous. Once I told the plumber, he seemed to visibly relax. I can't help but wonder what he thought it could be.