Answered by Shaykh Ilyas Patel
I have a question regarding the nature of semen. Is it true that once it hardens, that it is sufficient to merely scratch it off as Ayesha(ra) did when she spotted a speck of semen on the Prophet(s.a.w.) clothes? Is this hadith accurate? Also I have a scenario to present to you. I have a wetdream and the semen is contained in my underpants and pajamas (sleeping pants) and as a result the pajamas becomes a lil moist on the outside and will eventually rub against the blanket. Now there is nothing visible on the blanket, but is that part of the blanket najas? Please explain in detail. Jazakullahu Khair
In the name of Allah Most Compassionate Merciful
1) If the semen is dry then it can be scraped off and if it is wet it has to be washed away.
It is mentioned in Nur al-Idah as follows:
A cloth or a body can be cleaned by scraping dry semen off, whilst purity from wet semen is only achieved by washing.
(Nur al-Idah, Allam Hasan Shurubulali, Pg 58)
It has been mentioned in Bukhari and Muslim from Aisha (Allah be pleased with her) that she use to wash the semen from the clothes of the Prophet (Allah bless him and give him peace).Also it is mentioned in Muslim an another narration from Aisha(Allah be pleased with her)I remember myself that I use to scrape off the semen whilst dry from the clothes of the Prophet(Allah bless him and give him peace) with my nails. It has been reported in Bazzar and Dar al-Qutni also, that she said, I use to scrape off the semen from the clothes of the Prophet (Allah bless him and give him peace) when it was dry and wash it when it was wet.
(Hashiya al-Tahtawi ala Maraqi al-Falah, pg 132)
2) Semen is strong filth (najasa ghaliza) and if it is beyond 5cm in diameter then it is obligatory to wash the clothing. If it is less than this, then it is recommended.
(Nur al-Idah, Allama HAsan Shurunbulali, pg 53)
In your case you will have to determine how much semen is soiled with the underpant, though the blanket seems to be not affected by it at all, as you said it might eventually rub on from the pyjama as based on your possibility and doubt that you have.
Although in normal day to day life we tend to clean any amount of filth which exits our body though its proportion is overlooked in shariah.
And Allah alone knows best