Brown bagging it to work makes you feel like you’re in junior high. But your PB&J doesn’t have to be elementary.Trade store-bought jelly for handmade jam with local food writer and blogger Marisa McClellan’s Successful Home Canning classes. Take them in the comfort of your own kitchen with a group of friends or sign up for sessions at Foster’s (the next one is July 11; they fill up fast).McLellan, a repository of knowledge about everything preserved, will teach you how to jam like a pro in her 90-minute hands-on course. She comes armed with supplies and locally grown ingredients, so you don’t have to do a thing.If sweets aren’t for you, attend a demo of pickling Polish-style dills or tomatoes.Which run rings around Tater Tots and ketchup packets.For private lessons, e-mail Marisa McClellan (email@example.com). To see class schedule, go to shopfosters.com. For more information, go to foodinjars.com.