Bit of a weird one

[Jules-C]

Just ordered one.
If it's totally clogged up then I'd imagine the pipes are too with the yellow stuff.

I just cleaned old one out, I thought it was just sludge in it that's when I found it had bit of coarse sponge in it.  I thought about leaving it empty when put it back together to reduce chance of it blocking again but decided to push a bit of sponge in it in case it sucked unfiltered gritty air up into the air box. I know it wouldn't be much but doesn't take much to damage the cylinder bores