A 'smells of home' nap item for daycare, for a 5 month old. What did you send?

New note from daycare: please send a familiar item for nap time, something that smells of home. He's 5 months. He doesn't have a favourite anything yet, except the old T-shirt I wear at home, which he mostly chews. What did you send at this age? And is a soft toy or cloth in the cot even fine this young? Their nap room has those mesh cots.