Personally, I dread re-truing wheels which someone had built up with alloy nipples. If an owner had ever tried to true up a wheel even just a bit by themself, they had probably already rounded the nipples... and then, that's why the wheel comes to me.

Treat alloy nipples as if they are made of glass, lube them as others have advised, tension the wheels gradually, and be sure to use the correct size spoke wrench... "close enough" is very bad.

So many modern day racing wheels have now been built up with alloy nipples, I am seeing a steadily increasing number of "problem" wheels coming through the mill these days. Seems hardly worth the weight difference... IMHO.