fuel metering unit cleaning: advise needed

[Konstantin Bogach]

Hi.

I was testing injectors and opened metering unit: the cone is all
covered with something like oil with sparse sand particles stuck in it.
I did not look under the plate.  I wonder where this oily stuff came
from?  If I am there I want to clean everything. Will it be enough to
clean just cone surface above the plate?

Thank you.

Konstantin Bogach.
200tq '89
200tqw '89