Had when i worked in a preschool and kids love them! I would use colored sand instead of white salt. DIY salt tray with alphabet cards. Easy to make and kids have fun smoothing out the salt after correctly making the letter
*I've dont this* Even without writing in chalk, water painting on the chalkboard is amazing (read: clean) painting the kids love! Write letters in chalk and have child trace over with water. Just like wet/dry/try from HWOT! So easy
Many Montessori classrooms have a salt or sand tray for pre-writing work. We have a Corn Meal Tray. I love the feel of the corn meal and it makes for a wonderful tracing tool. Pretty simple and powerful tool. Inexpensive too.