Can I dye shirts/shoelaces with food coloring? Short on time/money.?

Trying to dye my undershirt and shoelaces green for St. Patty's day and have nothing else to dye with besides food coloring. I've heard something about vinegar. My original plan was just to soak them in food-colored water for however long and dry them somehow (not in the dryer, obviously) perhaps the oven?? lol. Anyway, whatever anyone else knows that'll make this easier please let me know.