The oral fleet laxatives are magnesium citrate... all forms of citrate that you can get into you will help.
I wouldn't put drinking one of those at the top of my list of ways to do it though.
If you try it don't go far from a toilet.
I've had to use those prior to medical testing before and Holy OMG...
They clean you out!
Another easy access form of citrate that you can take without those effects is Potassium citrate.
You can get that at any health food store in capsules.
I also take that daily, but bear in mind that I take a medication that causes me to deplete potassium I have to take it to replace. If I don't I get hypokalemia symptoms.
I do not however think that it would be a problem to supplement some potassium citrate short term to help pass a stone(say 200-300mg 2-3 times per day)... especially if you are drinking a lot of water and urinating frequently, which you certainly should be.
“You have your way. I have my way. As for the right way, the correct way, and the only way, it does not exist.”
And that's why I'm here eating HFLC Primal/Paleo.