This article is from the Food Preserving FAQ, by Eric Decker firstname.lastname@example.org with numerous contributions by others.
Connie TC wrote:
"Pump and Seal ( the hand operated vacuum pump, right?) I found that it
did seal jars fine but I didn't like putting a hole in lids-they seemed
to rust easily. But for plastic bags, while it could draw a vacuum it
was hard to get the bag closed before you lost it and the vacuum wasn't
as good as one from the Tilia vacuum and bag sealer machine, which I got
last year and really like."
Jay Heyl wrote:
"It does fine on jars, assuming you have a good seal around the rim. I
use it all the time for dry goods stored in canning jars.
With bags I would recommend going some other way. The Pump-n-Seal pulls
enough vacuum, but you need to be an octopus to work the pump, maneuver
the hose inside the bag, and then seal the top of the bag. There's also
the small problem that Zip-Locks are not vacuum tight."