What is the ruling on praying in a butcher's clothes that have spots of sacrificial blood on them?

Shed blood is impure according to the consensus of scholars. Clothes stained with it must be purified or changed before prayer, as removing impurity is one of the conditions for the validity of prayer. However, if the impurity is slight, like a few drops of blood, it is excused, especially for those whose professions make it difficult to avoid, such as butchers. The reference for determining what is little and what is much is common practice.