orthodox conversion to judaism

Cold utensils don't contaminate each other and when they have been used only in a cold state, they do not require kashering. The exception is for instance, the case where milk drops on a meat plate. If the milk remains there for 24 hours or more, the utensil becomes non-kosher.

Even cold utensils that were used for 'cold' foods, if the food was of a sharp nature, such as onions, they follow the rule for 'hot' foods. This is true only in a case where a knife was used to slice the food. This is due to the pressure caused by slicing.

In a case where food that was cut by utensils of the opposite type (i.e., a dairy knife cutting hot meat,) the cutting utensil requires kashering. The food may not be kosher depending on its size.

Glassware is usual considered parve and cannot take on the characteristic of either meat or dairy when they are used for frinking or eating but not for cooking. This is true of Arcolac and Corelle (not Pyrex).

Only fully metal utensils can be kashered.

We only kosher utensils from dairy to meat or vice versa when they have become non-kosher, or when we are kashering them anyway for Pesach. It is not allowed to kasher from one status to the other (meat and dairy) year around for mere convenience.

Plastic, sythetic rubber, melmac, porcelain, pyrex, Corningware, Teflon and Silverstone cannot be kashered.
When an article can be kashered, the rule is that "as it absorbes, so it will expel". Therefor, items used with liquids can be kashered with liquid. However, items used directly "in the fire", without liquid, such as a cookie sheet, are harder to kasher. These would need to be heated directly with a very hot temperature such as a torch.
Dishwashers can be used for dairy and meat utensils. This is true even with the porcelain lined dishwashers. Care must be taken to clean the drain before switching. However, it is necessary to maintain seperate racks for dairy and meat dishes. It is recommended, as well, to run the dishwasher with soap (empty) in between dairy and meat use. This leniency does not apply to using the year round dishwasher for Pesach.

Tablecloths and napkins can be used for dairy or meat procided they are cloth and not plastic. The tablecloth must be washed between uses.

A hot water urn can be used to place water in dairy or meat utensils. This is only true when the urn is not used for anything other than water or other parve substances.

Sinks should be used separately for dairy and meat utensils. In case of a sink that is not kosher, or when only one sink is available, a plastic tub or insert should be used. Only sinks made of metal can be kashered.

A blender or food processor needs separatre containers and blades for dairy and meat use.

The range can be used for dairy and for meat according to most opinions. The reason is that metal prongs are always in contact with the fire, making them kosher.

A refrigerator and freezer can be used for both dairy and meat products. Care should be taken not to allow anything to drip from the dairy to the meat products or vice versa.

When moving into a new home, where the dishwasher was, one should wait for 12 months before using the dishwasher. During this time, the dishwasher should not be used at all. After 12 months, the dishwasher should be run 3 cycles with detergent alone. At the completion of this procedure, the dishwasher and racks may be used.