Sentence:  I will redeeme all this on Percies head, / And in the cloſing of ſome glorious day / Be bold to tell you that I am your ſonne, / When I will weare a garment all of bloud, / And ſtaine my fauors in a bloudy maske, / Which waſht away ſhall <WSD>ſcoure</WSD> my ſhame with it, ... 
Meaning of the word marked with <WSD> tags:  To remove debris and dirt by purging; to sweep along or off (by a current of water).