I'm trying to clean this HEPA filter from my vacuum cleaner by washing* it and even though I've managed to get most of the dirtiness out, there's still some left sticking to the corners between each layer.
I can't reach there without a pointy object and I'm afraid of puncturing the sheet.
Do I need to clean that much? (how much suction do I lose if I don't)
What's a safe way to do so?
*I'm reading in some places that I shouldn't wash it, but the manual that came with my cleaner specifically told me to wash it. (and then dry)