TL;DR: Consult your LOR.
The CRC's website has a convenient chart of items that need toiveling, and for those that can't be toiveled, what should be done. For example:
- Coffee Maker - Glass parts - Tevilla. Machine - "clean well, do not use for 24 hours, and then run through one cycle"
(Note that the CRC includes this paragraph:)
Under no circumstances may something be kashered if there is a concern that it’ll break, as this might lead the person performing the kashering to be apprehensive and therefore not perform the kashering properly.For this reason, some items are listed as not being eligible for kashering even if technically there is a way that kashering can be done.
They do not mention George Foremans, unfortunately. Luckily, the Star K does:
- George Foreman Grill - Tevila w/o Brocha
- Toaster which will not break - Tevila w/o Brocha
The Kof-K says pretty much the same thing as Shalom did:
There is a dispute among the poskim if electric utensils require tevilah. Some say electric
appliances are not considered utensils and do not require tevilah at all since they are
regarded as being attached to the ground (while plugged in). Others say being
plugged in is not considered attached to the ground. Others say since electric
appliances may get ruined by toveling them there is no obligation to do so. Others say
one should take it apart and have a yid should put it back together. In this situation one
would not be obligated to tovel the utensil since it is considered as if the yid created a
new utensil. Others say that one should tovel such utensils and they will not get ruined if they are left to dry for 24 hours before being used. This is the custom of many
(I've omitted the sources, but they're all at that link.)
- Grill (electric “George Forman ” ) - tevilah - b’rachah
- Toaster - tevilah - no b’rachah (Some poskim contend that it requires no tevilah. Consult your Rav.)
The obligation to immerse vessels also applies to electrical appliances used in food preparation that touch the food directly (for example: a toaster, deep fryer, George Foreman Grill, or electric kettle).
Experience has shown that electric appliances can be safely immersed if, after the immersion, one allows them to dry for three days before plugging them in. To speed up this process, one can direct a fan at the area of the motor.