Should I be worried about the snails in my freshwater tank?

I have a small freshwater 5 gallon tank, with a beta fish, no filter system. My friend bought me two small snails from a local pet store, because algae was becoming a problem on the gl and ornament. I was trying to research about them, and have seen that snails multiplying is a problem, should I be worried?? I normally change the water and clean the gravel on a regular basis, and I was wondering how I clean the tank now that I have snails? How do you safely remove them to clean the tank?