canned air or related, need help with a product.

Solution
that 2nd one looks fine. Just remember to keep the can upright and if some of the propellant gas gets out (white, moist, freezes on room temperature) let it vaporize itself before turning power back on.
Shaking the can increases the release of propellant gas and as such, risk of it shooting out instead of air which is never the goal.
That said, it might help you squeezing last few bits of air out of nearly empty can but past that, no benefit and no real harm either if you let the can sit and stabilize a bit after shaking it.