Safe handling matters as much as product quality. Before each use, inspect the entire bag and cap for brittleness, fading, cracking, swelling or leaks. If anything looks wrong, replace it.

1. Heat water to a comfortably warm level, following the product instructions. Never use boiling water.
2. Hold the bag upright by its neck and pour slowly, keeping hands clear of splashes.
3. Fill only to the stated limit; many traditional bottles allow no more than two-thirds capacity.
4. Carefully release excess air as directed, then fasten the stopper securely.
5. Check for leaks over a sink before placing the bag inside a suitable cover.
6. Place it gently beside the uncomfortable area without sitting or lying on top of it.

Apply comfortable warmth for around 10 to 15 minutes initially, checking your skin regularly. Remove the bag sooner if your skin becomes uncomfortable. Never sleep with it against your body. Guidance from NHS services supports using a towel barrier and avoiding heat over numb or damaged skin.