Cleaning concrete calcium drips

Dang... It would be on the hood.

You'll want to go easy on the rubbing.
I've used "goo-gone" on a cotton ball to remove tree sap from my dark grey pickemup truck, so I can report that that's probably clear-coat paint safe, and it might be effective for this application.
If you go to the automotive section of your local store, you'll see a dizzying array of products to remove bugs and tree sap.

Whatever product you try, I'd use it first on an inconspicuous part of my car to make sure that it's clear-coat safe.

Good Luck!
Let us know what works for you!

 

Try a clay bar. I've used Clay Magic on my cars for many years. You can get it at most auto parts stores:
Clay Magic Auto Clay Bars - The Best Auto Detailing Clay Bar for Car Care

 

if it's really a calcium type drip, vinegar is the easiest, safest solution.