My kids have long gotten away with a dump, play, and walk away system at our house. It's always a fight to get things picked up. I'm working on easier methods of storing toys and books and having a place for everything and everything in its place (definitely the Montessori way), but there is a learning curve here. So I decided lets keep the trays but with new materials. The dry beans are now put away, and easier to work with objects are now in their place.
The tray that was our dry pouring activity has now been replaced with an activity to create shapes and letters out of craft sticks. I got the idea from Tot Treasure to put Velcro on the ends of the craft sticks to create shapes. I created cards as guides, and have included a work mat that's simply a folded piece of construction paper. My oldest can lay out the work mat. Choose a card and create the shape. I'll ask him to identify it and talk about it a bit, and then he takes it apart and chooses another card.
I'm still keeping the last tray with the pencils and eraser tops. My youngest absolutely loves doing this, and it's also helping with her colors. The eraser tops are a variety of colors so we can talk about the color as she puts the eraser on the end of the pencil.
Lastly, I've moved the kids table closer to the cabinet where the trays are stored. This way the kids have a much shorter distance to travel with their trays. I'm hoping this makes for fewer spills and increased confidence because they can make it to the table easily.