Why does my game work for several minute and then quit
My Nintendo will play for several minutes and then quit
A game console released in North America by the Nintendo Company in 1985, called the Nintendo Entertainment System, model NES-001.
It could be that your 72 pin connector is faulty, which is a known issue.
The pins could be corroded, filthy or they lost tension after all those years, which results in losing connection with the cartridge.
The best choice is to replace that connector, even if it's only a preventive measure.
As for cleaning the game cartridges, just take a bunch of q-tips and a "high concentration" rubbing alcohol.