As Neil says, it's probably dried-out grease. Try squirting WD40 on the shafts where they come out of the car, otherwise re-grease the joints inside the scuttle panel and WD40, then spray lithium grease in the shaft where it comes out of the motor.
And as Peter says, manoeuvre very carefully around bonnet base to avoid scratching scuttle panel. Best done with a second person. I used to get a pencil and draw a line where the bonnet sat where it was bolted on (so I could bolt it back in exactly the same place), then loosen those bolts so I could pull the bonnet out to maximum. Good to also put a thick towel or similar in between as it's really very easy to scratch the scuttle panel on the end of the bonnet.