Playmobil uses tampo printing now. Not sure about the older prints, but in most cases (and this works for me) you can soak the part that has the print in PINESOL for a few hours, then, gently brush the paint off (while submerged) with a soft-bristled toothbrush, then rinse off in water. That way you don't have to damage the plastic with harsh thinners or sand paper.
The only downside is the strong smell of PINESOL (which I soak outside on my patio) while you're using it. But this is a proven technique with most modeling I've done that required factory prints to be removed.
