sully your hands
sully (one's) hands
To partake in particularly underhanded, illicit, or illegal work or activities. The public can't be allowed to think that I, a senate hopeful, would ever sully my hands with a tax-evasion scheme such as that.
sully your handsFORMAL
If someone sullies their hands by doing something, they do something unpleasant or wrong. He had no intention of sullying his hands by playing politics. He would not sully his hands in trade. Note: To sully something means to stain it.