Subtle Transformation

Debasing a coin was the act of reducing its value while keeping its original face, usually by supplanting the precious gold or silver with cheaper metals like copper or zinc, thus in effect creating more money. 

It was done in times of need to raise money but it caused inflation for the populace.

However despite its flaws, it was a fairly common practice throughout the past and present world, because it was a very easy and lucrative fix to an enormously complicated problem.

Hence Alexander also believed this to be the main cause why the courts failed in their endeavors to stop coin clippings.

Too many of the nobles themselves were involved in it.

There are even regular instances of rival nobles attacking each other's currencies using this method, hoping to shake the other's economy. 

Thus given the enormous benefits involved, Alexander felt there was not a united will to tackle this issue.