Lot of 3: Russian Soviet CCCP USSR  Lapel Pin / Badge

I don't know much about these pins except that they were purchased in Russia about 10 years ago.

One says, Москва [Moscow] on it and has МЗСИ and something resembling Ц10К stamped on the reverse.

One says, CCCP ОЛЕТ 1967 Арте́к, on it, which may have been a pin from something like the Boy Scouts, but that is only a guess.  This pin is stamped with ЗТК on the reverse.

The third only says 1941 1945 on the front and is stamped 15K and a symbol I don't recognize on the reverse.  

I've included close-ups of the markings on the back-sides of each i ncase they are important for identification.

Please contact me with any questions.