Saline is available over the counter although a warm salt water mix works just as well.
If you think it may be a blocked tear duct you can gently massage under the eye in the direction of the duct to help clear it. Follow up with a saline/BM/salt water was. Always wash from the inside out (nose to cheek) and always use one cotton wool ball (or whatever you're using) per stroke (so as not to re-contaminate).

HTH

MG