Without these three major factors, proving that an oral contract was agreed upon can be difficult. If you make an oral contract with a stranger in business dealings then one of the two parties could easily deny ever agreeing to an oral contract or claim that such an agreement was not made in good faith.
There are two components to slime. There is a borax and water solution and a glue, water, and food coloring solution. Prepare them separately. Mix 1 teaspoon borax in 1 cup of water. Stir until the borax is dissolved. In a separate container, mix 1/2 cup (4 oz) white glue with 1/2 cup water.
Assuming you can get hold of PVA, it is a fairly simple process to make slime. First, mix a 4% solution of PVA and water. 4 % would be 40 grams of PVA to 960 ml of distilled water (of course you can adjust and make more or less). Wear a mask and have plenty of ventilation when doing this!