I dread to think what could be on them. It would be better to use a fresh pair but if you insist on wearing them give them the most thorough cleaning ever followed by an overnight soak in your disinfecting solution. You don't want to give yourself an eye infection, they can be nasty.
It depends on what kind of dirty on your contact lenses. Whether it can be rinsed out or not. If you can clean the contact lenses thoroughly, you can use the contact lens again. The most important thing is that you need to make sure the contact lenses can not infect your eyes with bacterial or other organism. However, the best and safest way is to change a new pair. Hope this helpful.