Easier way to shell out sunflower seeds

I like the taste of sunflower seeds, however I really dislike the process of shelling them. The bags say "Eat. Spit. Be happy." But I have found that shelling it in one's mouth is not only messy, it also tends to splinter the shell and hurt gums. I have tried shelling them out by hand, but that is exceedingly time-consuming.

I know they can be purchased shell-less but I was wondering if there is some trick, as I like some of the seasoned kinds, just not a fan of the process. Any trick to unshell multiple sunflower seeds efficiently?