Years ago, I set up a process for emergency savings that has worked well for me and my friends. Perhaps it can work for others.

On the first of the month, open a 3 mo CD with (hopefully) the amt needed to meet one month's expenses. Do that for 3 months. Then forget about them. You now have a CD maturing every month earning more than "mattress money" and far enough out of reach for an impulse purchase. If you don't have enough saved to cover a whole month's expenses, deposit what you can and add to the amount as the CD matures and rolls over.