Most of the time I both scrape the gills off portobellas and, with the larger ones especially, peel the skin off as well.

It's not just the ichy gray color. The gills, particularly if they've opened, make everything taste like dirt. They also start to decay long before the meat of the 'shroom; another reason to discard them.

Thanks Brook I Am Glad To Know That, And You're Right They Do Taste Like Dirt.

But they're easy enough to clean, Cathy.

Just take a regular teaspoons and use it to scrape them away, using the point end to get up under where the caps overhang.

To peel them, just pinch the edge of the cap and pull. The skin comes off in sheets.

What you're left with is the beautiful tasty white mushroom meat, which has a earthy flavor, but doesn't taste dirty.