
I suspect warts , they are easily removed by a podiatrist . If you are on east coast I recommend The Foot Clinic in Harlem ,New York
They look like warts or verrucas caused by a virus. If you are in UK there are lots of products you can buy over the counter. However,as you have had them for a while and they look quite large,you may find a GPs advice better.
Alternatively,pay to see a chiropodist. It will be worth it to get rid of them.