Raised irregularities in a magnetic data storage disk are removed by contacting an MR head with the relatively softer irregularity to abrasively erode the irregularity. The MR head may be brought into contact with the irregularity, for example, by selectively increasing read bias current of the head to expand the head toward the disk. Advantageously, removal of such imperfections helps eliminate thermal asperities created when the head inadvertently contacts raised irregularities during reading of data.