The Secret of the Angel - start by opening one hint at a time to see if it's enough information
Something is hidden in the wings of the angel, under Mr. Uldahl's red and yellow scribblings? But how to remove the red lines?
If you just had a red lens. That would neutralize all the red and yellow lines.
When put in the red plastic envelope, the red and yellow lines disappear. You should now be able to read 5 + 2
The right number and second digit in the code for the USB-stick is therefore 7