I usually put Romaine and other leaf lettuces in a large baggie with a DRY paper towel around it.
But I have recently discovered a remarkable product at Amazon that works to keep all produce longer without spoiling....as in like fresh raspberries for over a week! It's calledBluapple and is a set of 2 little blue balls that open to contain a little packet of stuff that "eats" the ethylene gas that produce makes. I use one in each drawer. Check them out!
https://www.amazon.com/Bluapple-2-pa...+produce+saver
Jan in VA