Airtight bag seasoning is the classic product manufactured by R.G. Hardie, and which is recommended by most traditional bag makers. It comes in an 250 ml plastic bottle, and can be warmed in water, or in a microwave (remove the cap first!). We recommend adding small amounts at a time, rather than using the amounts given in the directions. We like to season the bag sparingly and as often as necessary, rather than 1/2 tin and draining, which leaves you with stocks to clean, and often excess seasoning in the bag.
This is a fantastic product, and will last a long time if you store it in the refrigerator.