So if it's a utensil that was used for liquids like a pot, how is it kashered? by dipping it in boiling water so it can expel- if it's a utensil that wasn't used for cooking like silverware and was used to eat something non kosher with a different dish like a plate, or if it touches something non-kosher that was hot (heat causes the utensil to absorb) so the kashering process would be the same. meaning - he can take the silverware, place it on a tray or on the counter- and pour boiling water on it meaning,he does not need to immerse the silverware in the boiling water, he may just pour the water on it because the law states: "as it absorbed so it has expelled" the same way the utensil absorbed the prohibition it will in the same way expel it. as opposed to this- skewers for instance, if used to grill non kosher meats- they would also be kashered on the grill/fire. 