Note that, packaging and transportation can indeed cause some moulds to deform. Soaking the mould in hot water and then using rice to help reshape it is a practical solution.
Here are a few additional tips for mould remediation:-
1. Freezing Method: If the mould is made of silicone, you can try placing it in the freezer for a few hours. This can sometimes help the mould return to its original shape.
2. Supportive Fillers: Besides rice, you can use other fillers like sand or small beads to help reshape the mould. Make sure the filler is dry and can conform to the mould’s shape.
3. Gradual Heating: For more delicate moulds, gradually heating them with a hairdryer can help. Be careful not to overheat, as this can cause further deformation.
4. Storage Tips: To prevent future deformation, store your moulds flat and avoid stacking heavy items on top of them. If possible, keep them in a cool, dry place.
5. Use of Weights: After soaking in hot water, place the mould on a flat surface and use weights to hold it down in its correct shape until it cools and hardens.