Errr... are wa talking plastics or metal models here? I'm not too familiar with Tau...
For metal miniatures, I'd suggest chemicaly pure acetone... There's also acetone with oils in it, but oils are a no-no with miniatures as they cover the whole mini in a thin film of oil which will mess up any primering attempts.
There are alot of other things you can use though. Citadel primer comes of really good with acetone though, I've used it on several models and the best thing is that it's readily available in just about any grocery store here in Sweden.
For plastic miniatures, there are not as many options as most things powerful enough to dissolve the paint will also damage the plastic miniature itself. Many people swear by break fluid, I've never tried it though - but from the opinions I've heard I'd say it's the best choice. Just be careful and try it with one mini first, to make sure it doesn't mess up your mini!
I'm pretty sure a glass of coke will do nothing about the paint, and any paint removed would come from the scrubbing.
For any method above, you'll have to soak the mini for a while. Also, don't over crowd the container in which you do the soaking. If you're using acetone, do it in a glass jar or metal container. It's possible to re-use acetone for a batch or two. Brush the models with an old tooth brush. First do it with a little acetone in the brush (just dip it in the soaking container), and then do it under running water to rinse off the acetone and peelings. Finally dip the model in hot water with dishwashing liquid in it, to remove any chemical residues etc. Don't know how important this is, I don't really think it's needed after soaking something in pure acetone - but do it to be on the safe side.
Same procedure for the break fluid, but be sure to rinse it with water and soap at the end.
And Vycos, sorry about the thread jacking.
Excellent post and sound tips!
/Phreedh