I found some stains after a week of daily use on the spine of my first razor, an entry level 5/8 TI, despite methodically washing the blade with the hottest water from the tap, drying with ultra absorbent kitchen paper towel and leaving it out to air in the bedroom.
Those stains could be caused by soap residue or by minerals in the water. Alcohol helps mitigate both (the first better than the second). You may wanna try it as an experiment.