• First, make sure the playdough is fixable. If the playdough is as hard as a rock, you won't be able to bring it back to its soft texture. This hack works for dry, crumbly dough that you can still squeeze in your hands but that needs some pressure to be squeezed - see my pics above.
• Place a small batch of dry playdough - about 60 grams - in a microwave-safe bowl.
• Spray some water 3-4 times onto the ball using a spray water bottle.
• Microwave for 10-15 seconds, then transfer the dough to a plastic bag - the bag prevents burning yourself as the dough is hot and sticky.
• Squeeze the bag to knead the dough with your hand for about 30-60 seconds.
• When the dough is softer, doesn't stick to the bag anymore, take it out and play with it!
• Depending on how dry your playdough was, you may have to repeat the steps above.

Downsides

• The dough will harden again after about 1 hour of play or when it cools down. Repeat this hack when needed.