To get around this problem, we started using laser-printed labels a couple years ago with very good results. We print them on acid-free paper in the smallest readable font possible, cut to the edges of the text, and sandwich the label between coats of Acryloid B-72 with tweezers. No smudging and the label is always legible. I have attached a photo of why we started doing this – some of our archaeological collections were labeled with provenience info in ink that had started to fade. Eek!