Oil change - found some bits in the pan

[Goran]

Is it normal to have a bit of swarf come out during an oil change for a 100k mile car?
I did a 3rd oil change by myself, after 8months and 4000 miles, and this time round I decided to sieve the oil as it came out with a fine sieve - except I forgot to do the same when emptying the filter housing. So I dont know if the bits are from this oil change or previous - sieve didnt catch anything I found them in the oil pan when I was panning for gold

The black bits are crunchy and fragile.

Any shared experiences much appreciated.