These dark gray stripes running down the front of gutters due to molecular bonding of pollutants to the aluminum. Here's what to do to get rid of them.
Technically, yes, you can lean an extension ladder directly against a gutter, but I generally wouldn't recommend it. Here's why...
When you boil it right down, your house only has 8 things you REALLY need it to do for you. It might sound simplistic to boil it down like this, but I like to think of it as getting to the first principles of a house.