The World Federation One Stop Fiqh

Ruling 891

If the ḥaṣīr30 or carpet of a mosque becomes impure, it must be washed; and if cutting out the impure part is better, it must be cut out. However, cutting out a considerable amount, or making it pure by causing damage to it, is problematic [i.e. based on obligatory precaution, it must not be done], unless leaving it causes disrespect.

30 A ḥaṣīr is a mat that is made by plaiting or weaving straw, reed, or similar materials of plant origin.