If i can't wash my hands, are hand sanitizers a good substitution?

Yes: But washing hands properly with soap and water is better.

Partially: Hand sanitizers kill bacteria, but they don't remove dirt or other things that accumulate on the surface of your skin. Practicing regular, thorough hand washing is very effective. It can be supplemented by gel sanitizers when washing isn't available, but the use of both, in moderation might lead to the best results.