I think it would be a very nice change if you chose another type of food to prevent this finicky behavior that is wasting your money. What I do is purchase a few different kinds of foods and mix them all together in a large container. It lasts for very considerable amount of time for the money and you can pick out the corn and such you don't want them stuffing on and save them for treats.
Sunflower seeds are actually VERY healthy and don't really need to be taken out unless there are tons of them in the same bowl. (Too much of anything is bad blablabla hahaha.)
A good mix would need a lot of fiber, less sugars, some protein (Like meal worms or boiled chicken.), of course fruits and vegetables and some dairy like cheese and yogurt drops which provide vitamins and minerals.
I prefer to use Hazel Hamster (Harry Hamster), Carefresh Complete (One of the healthiest choices as it has Omega 3 and no dyes.) and Mazuri (Blocks that are the best in nutritional value.). Sometimes I add some bird seed mix, so no it is not dangerous to feed them this but only in small portions (like treats on the food) rather then the food itself since they have a lot of sugars.
I usually just mix all of this and it lasts me almost 3 months as I portion food to my Hamsters every other three days.
If you just want to focus on one food that is usually pleasing to most Hamsters, I would go with Carefresh Complete or Hazel Hamster. These are also great with Diabetic Hamsters, just pick out most of the corn and you are good!