candied ginger is very good for nausea and keeps in the fridge practically forever. Also, a peppermint altoids works great after you drink the oo/grapefruit mixture. It kind of takes your mind off the bad taste and if you don't eat candy anymore it's like a little reward for being so virtuous. It also helps take the edge off my self pity :)
Also, I've found it much easier to drink it through a straw placed well back in my mouth. That way you really don't taste it much and it doesn't get all over your teeth. If you really hate the taste of olive oil, you could use safflower which is pretty tasteless. Believe it or not my teenage son said he liked the taste of the oo/grapefruit mixture (at least the first half of the jar!)