Answer:

I say, and with God's success: Throwing slime and mucus into water is disliked; because water is a means of purification, it should be protected from impurities, and both are considered repulsive by nature, so throwing them into it is disliked. The same ruling applies to everything that is considered impure. Refer to: Tabyin al-Haqaiq 1: 7, and Al-Hadiyya al-Alaiyya p. 26, and God knows best.