Have you seen a lot of metals in your home? There were rubles, too. The Olympic...

You guys are probably confusing something. Half-tinners, or coins of 50 kopecks, were sufficient, as were metal rubles and the rest of the exchange coin. Notoriously rare were banknotes of 50 rubles and 100 rubles (sandwich) and only because the latter exceeded the salary of the majority of the population of the USSR.
Ask people over 50 years old, for example.