Reference: Fataawa li Ahlil-Mayyit – Question 5, Page 10
Fataawa wa Rasaa.il Shaykh Muhammad ibn Ibraaheem – Volume 3, Page 190
Question: If the shroud is stained with impure water, then what should be done?
Response: If the shroud is stained with impure water, then it is imperative to wash it and purify it, then dry it, or replace it with another shroud. And it is not correct to perform the funeral prayer over the deceased with this impurity [on the shroud].
And Allaah [alone] has the Complete knowledge [of all affairs].