Simply remove them and keep a close eye on the state of things at every oil change. You can't find out anything more at this point without a total teardown. If there are no other signs, don't panic. I found large, curled bits of aluminum inside my filter housing on my c280. That was 200,000km ago. I still don't know what they were, nor do I care (yet).

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'96 C280 (gone)
'97 C36
'05 C230k