Engine oil seals

So...

As some of you may have guessed from other posts I am neck deep in an engine overhaul on my 1995 M600, and I have stumbled across yet another curiosity.

In the clutch cover (aka: the RHS engine cover, since the M600 has a wet clutch it is all one cast part) is housed the engine oil pressure switch. On the inside of that mounting point is an oil seal which seats on the crankshaft.

Behind this oil seal (are you still with me?) is a gauze/perforated sheet/strainer of some description.

Here lies my question: can I remove this gauze? And how? And what is it?

I am trying to blast clean the entire engine whilst its apart since it is corroded all over.