If you look closely at my left thumb in the picture below, you’ll notice some black at the top of my thumbprint at about my knuckle. I’m an avid cyclist and take care of my bike after every ride. That care includes quickly cleaning and lubing the chain. The black on my thumb is bike grease.
I’m also a relatively recently reformed perfectionist. It’s not that I am or was ever a neat freak. But for years I preferred things more on the “just right, symmetrical” side of life than the “just leave it alone; it doesn’t matter” side. For example, if the kids left their dishes in the living room after they went to bed, I put them away even if I was bleary, bugged eyed tired just so I wouldn’t be greeted by those same dishes when I got up in the morning. But now - hey, just the other night I did this - I get the kids to put their own things away even if they don't do it right away - and I feel better about it.

So, back to my thumb. As soon as I noticed grease in some of the Gotta' Eat, Can't Cook: "Show Me How" Picture Book Cooking photos that included my left thumb, I thought, “Oh God. I’ve gotta’ re-shoot every darn one of those shots” and make sure that thumb no longer has any grease on it. So, first thing - clean that greased up thumb. I used dish detergent, tried a jug of gritty, industrial hand cleaner, used a firm brush and even thought of using power tools - my basement’s full of them. Nothing worked.
But, then I realized, “Hey, you’re making yourself crazier than you already are. So, stop it.” And I did. What I’m trying to do to help you in the kitchen is not about being perfect. It’s about helping you get done what you need to get done as honestly and easily as possible.
For the record, I wash my hands well whenever I handle food, and though I sometimes still have grease on my thumb, it’s just as much always darned squeaky clean - and I (and my bike) even feel good about it.