Oil Change?

I have been oil pulling for a couple of months with some really good results more energy, feel lighter and happier, feel cleaner my jaw used to creak a lot this has gone away - I used to have amalgams. However, the black ring around the toliet is disgusting looks like mould to me!

I decided to change oils from sesame to sunflower noticed a slight different. Not as profound as when I first started but seemed to be able to concentrate longer throughout the day.

What's the best time to switch oils and which oils give people the best results? I've tried coconut for a couple of days. I have thought about walnut and pumpkin seed oil anyone use these?