if a person has traces of semen on his underwear, is he allowed to pray or study Torah? because it's forbidden to pray when your garments are not clean.
If it is touching one's skin he should be stringent and not pray while wearing such garments. However, if it's on his garments and covered, so that it is not visible nor touching his skin it is permitted according to all opinions. However, even in such a case it is best to wash it or remove the garments. (MB 76:15)
