Breast pump question for moms with a couple kiddos!

Noel
I have a breast pump from 2013 that I used with my daughter. My question is do you all think I should purchase a new one for my little guy (June 2016)? Can you cross contaminate with your own milk and cause baby to get sick? Or would you think it would be OK to reuse my old one?
Furthermore, how do you all sanitize yours? I'm worried that even though I cleaned it 2 years ago that moisture got inside and could have mold spores where I can't see. I'm thinking run vinegar or rubbing alcohol, then water?