>>>It takes years for the body to reject the foreign substance and expel it? I've never heard of that. I've heard that sometimes it can take a few months for foreign objects to be expelled through the skin. Amazing...
>>
>>The doctors told my brother (and this was around 1970) that glass isn't seen as a foreign substance by the body. Seems many metals aren't either, and some plastics I guess.
>>So it just kind of works its way up over time (cell replacement and such, I suppose).
>
>I got a shard of glass in my toe once in July. It came out in November. I guess stepping on it all the time didn't help speed its exit.

In my brother's case it was anything from near microscopic pieces (caused bleeding) to large pieces up to a few cm. Glass is also not detectable via X-ray.