Mangos should be ripened on your countertop, in a paper bag, or in a cardboard box. Plastic bags are just for convenience when purchasing. Please take the mangos out of plastic bags as soon as possible.
Treat Mangos like Bananas. Temperatures below 55 Fahrenheit will damage the fruit. Extended chill will make most mangos taste like sweet mush. I leave cut up mangos on the counter. Whatever isn't eaten in a few hours, I freeze.
Some mango varieties might not appear ripe when they actually are. Usually the best way to judge ripeness is smell. The skin of Keitt, Petegrew, Mallika and Carrie will often be green when ripe. Also, Petegrew and sometimes other varieties can take weeks to ripen.