Originally Posted by
RussianTexan
Out of curiosity, how would you go about canceling that particular stamp? The office that takes care of the internal passports? Is that the local branch of the MVD?
You take your "foreign" and "internal" passports to the Ministry of Foreign Affairs (MID). It has offices throughout the country:
http://www.kdmid.ru/cd.aspx?lst=cd_wiki&it=/Список представительств МИД России на территории Российской Федерации.aspx
The offices are typically open twice a week, so you have to check their schedule ahead of time. In my case, it took five minutes. Good luck.