We do try to avoid plastic and I LOVE glass jars for EVERYTHING! I put leftovers, canned beans, hummus, guacamole, coconut milk and so much more in glass jars we get from the grocery store. I have been collecting them for years so I have a wide range of sizes. One of the most used is smuckers organic peanut butter. they are the perfect size and have a wide mouth. We also use glass jars as drinking glasses.
as for baby poo.... I love the ecostore bleach alternative, it's like oxy clean. I fill my laundry room sink with hot water and some of that and soak overnight. If that doesn't get it all out I lay it out in the sun too. :)
hope that helps!