From: Rabbi Moshe Sofer
To: Rabbi Sender Meizlish
When an Aleph's Yuds are fully fused to the middle bar rather than connecting at their thin edges, the Chasam Sofer rules that the adhesion may be scraped even within Divine Names. He argues that erasing part of a Divine Name for corrective rather than destructive purposes does not violate lo sa'asun ken, and reasons by kal vachomer that if scraping adhesions between correctly written letters of the Name is permitted, certainly one may correct a letter whose form has been entirely ruined.
Source: Shu"t Chasam Sofer YD §267