´It was narrated that 'Aishah said:` "I remember when I found it (semen) on the garment of the Messenger of Allah and I scratched it off."
Explanation & Benefits
Maulana Ataullah Sajid
This ruling applies in the case when the semen (madhiy) is so thick that, upon drying, it can be removed by rubbing. If it is thin, then it permeates the fabric and leaves a stain. In that case, it is not cleaned by rubbing. In such a situation, it is appropriate that the affected part of the garment be washed so that cleanliness is achieved.
Source: Commentary on Sunan Ibn Mājah by Mawlānā ‘Atā’ullāh Sājid, Page: 539