Should one make sure his hands are clean and free of all particles before washing? I’m not really makpid about any ink marks or particles in general; do I have to make sure my hands are free of such things?
One must be careful that one’s hands are free of dirt that one is generally makpid (particular) about. Even if one is not particular about the type of dirt, but people in general are particular about the type of dirt, one must also ensure that hands are clean of it before washing. It therefore depends on the particles in question.
For ink marks, although most people are probably particular, stains that have no substance do not constitute a chatzitzah (Mishnah Berurah 161:14).
If one washed without cleaning off dirt that one is not particular about, but that most people are particular about, one should wash again without a berachah, because this question depends on a dispute among poskim.
See dispute between Rambam (personal, subjective), and Rashba (objective) concerning the question of dirt that most are particular about and the person in question is not particular. We are concerned for both opinions on a lechatchilah level (Mishnah Berurah 161:7, 10, citing from the Magen Avraham).