Supermarket own brand cheapest shampoo makes a perfect Play Slime! Less than 50p for a big bottle and no preparation time needed. It smells great and pearlescent ones are super for mark making.
We added sparkles, scoops, beakers with holes in and a cheap helter skelter toy (marble runs also work very well).
The key is it has to be viscous enough to move nice and slowly!
Creative messy play toddler classes for babies, toddlers and preschoolers in Cheltenham.