A solvent-free, operationally simple, and chemoselective mechanochemical method for t -butoxycarbonyl (Boc) deprotection is described. In a planetary ball mill, N -Boc groups from protected heterocycles, amides, and anilines, as well as O -Boc groups from carbonates, can be removed selectively, using basic alumina. This high-yielding protocol avoids tedious extraction and column chromatography.