On the way, he stopped and prodded the boy with a long, dirty finger.

He squeezed water from his eyes with a dirty finger, then smiled at her.

You must not touch your eyes with your dirty fingers.

He raised a dirty finger and pointed to his left.

You don't have to come and put your dirty fingers on me.

For instance, a dirty or marked finger is difficult to image properly.

I feel as if his dirty fingers are on my soul.

Her dirty fingers rose, holding a small, greenish bit of material.

She lifted her hands and looked at her dirty fingers.

"Over that way;" he pointed with a dirty little finger in an entirely wrong direction.