How can they "wash away" the caffeine from Nescafe Gold to produce that "de-caf" version?
In general they use different types of solvents and methods to wash away the caffeine (or at least a great percentage of it) from the coffee beans , you can find more information here : https://www.todayifoundout.com/index.php/2011/04/how-decaffeinated-coffee-is-made/