Rain, the 1831 5 kopek is pretty common especially if it's from the EM. As well as to add the fact that it's low grade and cleaned, I don't believe you can get 10 dollars for that, unless you find a desperate person to add to his type set
The 1957 kopeks are pretty unusual because of the ribbon counting, I believe it was 15 versus the 16 previously used (or I can be terribly wrong) which makes it a one year type. Not a bad coin though in UNC as Soviet coins are often circulated.