Fill the empty glue bottle about ⅓ full with warm water (about ¼ cup) and seal with the lid. Shake well to combine the remaining glue with the water. Pour into bowl with glue and stir to combine.
Add the baking soda to the glue and stir to mix thoroughly.
If you are adding glitter and confetti, stir them into the glue mixture.
Add contact lens solution to the glue mixture and stir well. (Note: regular glue will require less contact lens solution than glitter glue. Add the contact lens solution slowly, mixing between additions, and add only enough to bring the glue together into a soft ball.)
Remove the slime from the bowl allowing any excess liquid to remain in the bowl. The slime will be sticky. Begin to play with the slime, kneading it as you would bread dough, to bring the slime together. The slime is ready when no longer sticky.
Best if stored in an airtight container in the refrigerator when not in use.