Methyl Cellulose also referred to as Methocil, comes in powder form or pre-mixed. Non-toxic and non-allergenic. when added to water it creates watery slime to very thick slime!
Ratio for thin slime is 6 oz of powder to 4 quarts of water. Medium slime is 8 oz of powder to 4 quarts of water. Very thick slime is 11 oz of powder to 4 quarts of water.
Best way to mix is adding half the powder to 3 quarts of very hot water and mix until it dissolves. Then you can add the other half of the powder, mix well and finally add the last quart of room temperature water and mix. You can also add food coloring to get various shades.