There are several ways to kill crickets instantly, according to the search results:

• Pesticides: A pesticide containing a pyrethroid (such as cypermethrin or bifenthrin) can act very quickly and begin to kill crickets within minutes.
• Dish soap: Mixing dish soap at 1 oz. per quart of water can kill crickets in about 35 seconds.
• Vinegar: Mixing vinegar in water (at 4 oz. per quart) can kill crickets in about a minute.
• Molasses: A few drops of molasses in a small bowl of water will attract crickets into the water where theyll drown. Similarly, mixing 3 tablespoons of molasses with two cups of water and setting the mixture out in a mason jar can lure crickets in and drown them.

Its important to note that some of these methods may not be safe for use around children or pets, and its always best to follow the manufacturers instructions when using pesticides.