It doesn't make sense to me to keep cleaning with dirty oil and dirty saliva.
If the thinning and whitening of the oil is due to it filling up with toxins, why wouldn't you want to refresh with new, thick/clean oil? Alot of the enzymes are still floating around your mouth and sitting on your gums anyway to refresh the new batch of oil.
It's like if you're all sweaty and feeling gross after a workout, do you shower to rinse it right off or do you soak in a tub and sit in sweaty, dirty water?
If you're washing a floor, once the water in the bucket turns black do you keep using it to wash the rest of the house or do you dump it and get some clean water?
I don't know much about enemas as I've never done one, but I don't think you reflush your colon out with dirty, toxic water either...
Just my take on it anyway.