Anyone trying the trick should use a clean, empty bottle that is in good condition. The cap must be secure, and the bottle should contain no water, detergent, or chemicals. Never use a damaged bottle with cracks or sharp edges, since it could break during the wash cycle.
The trick is better suited to ordinary, durable clothing than delicate fabrics. Silk, lace, fine wool, and other sensitive materials should always be washed according to their care labels. Washing-machine manufacturer instructions should also take priority over any household experiment.
