I used to not be a fan of castor oil oping-- now I keep a bottle in the shower and OP in there. After the first...oh, say, five times, it's not disgusting like it was initially and as someone else mentioned-- it starts to give an aftertaste of peanuts.
as for whiter teeth, what really helped me was brushing my teeth with natural bar soap, and then occasionally I brush with Virgin Coconut oil (or swich with that.) My teeth (I belive) have gotten a shade or two lighter and I can see spots lightening up that shows I still have farther to go.