After preparing items for הגעלה, one must remember the following: We follow the concept of רוב תשמישו, the way it is used most of the time. Most utensils can be kashered with this purging in boiling hot water.
The principle is that the heat of the boiling water will pull out whatever absorbed tastes there are in the specific item. This includes things made of metal and wood and even plastics. Glass doesn't absorb but is still effective with הגעלה according to Rav Avraham Yosef, son of Rav Ovadia זצ״ל.
Our primary problem is with earthenware vessels such as china that may not be kashered. Earthenware only absorbs and the heat does not help.
Remember that silverware can easily be kashered and used on Pesach.
Yeshurun Synagogue on King George is offering free הגעלה on Wednesday and Thursday evening and Friday morning.