Wet a stainless steel scourer in warm water mixed with a little washing up liquid. Then vigorously rub the surface of the wok inside and out to remove its protective coating. Make sure you don’t miss any area.
Rinse thoroughly then wipe dry with a kitchen towel.
Burn it empty
Place the wok over a burner with high heat. Burn it thoroughly. You’ll notice the colour changing during this process, from silver-grey to golden, brown, a metallic rainbow shine, then finally settle down to a bluey grey colour.
To make sure it's entirely burnt, hold the handle and move it in different directions so that each part has a chance to be in direct contact with the heat.
Once all is done, let it sit for 5 minutes or so until it’s cool enough to handle.
Burn it with a little oil
Pour a little oil into the wok. Use a piece of kitchen paper to rub the oil around the inner surface leaving just a very thin layer.
Burn it again over high heat. Focus on one area at a time. You’ll see smoke rise from the heated part and the colour darkens. When there is no more smoke appearing, move on to another area.
Once you’ve burned off all the oil coating and no more smoke appears, the wok should have gained a greyish black finish.
Leave to cool then rub another layer of oil and repeat the procedure. Then your wok is properly seasoned and ready to be used.
Clean it after cooking
Right after cooking, rinse it under warm running water and use a sponge or a brush to remove any food and residues (use a little detergent to remove grease if necessary). If there is burned food hard to remove, fill it with hot water and leave to soak for a short while. Then wash it using the same method.
Use a cloth to wipe off any water inside and out. Then place it over a burner. Turn on the heat to dry it completely (don't skip this procedure).
If you don't use the wok regularly, or your kitchen is humid, I suggest you coat it inside and out with a very thin layer of oil once it has cooled down.
Video
Notes
1. Re-seasoning: You can use the same method to re-season a wok if it has got rusty spots or has lost its non-stick patina layer.2. Since the acid in food could remove the patina built upon the wok's surface, make sure you don't cook ingredients that are highly acidic in the wok for a lengthy period.3. Do not use the wok as a storage container. Transfer the food to a serving plate/bowl as soon as it is cooked.4. Do not clean your carbon steel wok in a dishwasher.