Discarding oil and teeth cleaning

I have just started pulling. I use coconut oil. Because it solidifies at 76 degrees, I don't want to put it down the sink or toilet, as I don't want to risk messing up our septic system or plumbing. What to do with the oil I spit out is a problem, and I have started spitting into a small plastic bag, tying a knot in it, and throwing it in the garbage. This doesn't sound too sanitary, but I don't know what else to do. Any ideas?
Also, when I brush my teeth afterward, I use baking soda and dilute hydrogen peroxide for its anti-bacterial properties.