How deal with mentally ill co workers.?

I work at this job where I work with these guys who seem to be mentally ill . They fallow me, ask me out, talk dirty to me, blew kisses at me, make noises at me every time I walk by them , exc.. I'm only 19 . They are 2-12 time my age . It pretty gross. I had to show them my work id card to to prove that there to old for me . I don't think they understand they are too old for me. some of them are actly mad they got move to a different part of the company. What should I do . I'm getting annoyed . Advice appericted.