I read on here that everyone sifts everything, especially cake mix. Well, I tried it, and I must be doing something wrong. The cake mix totally gummed up my sifter, and I had to give up. I just use a small, handheld sifter with the hand grip that you squeeze. What am I doing wrong?

Everyone sifts everything?? I don't think so!

For one thing, put that handheld sifter in the garbage and get a good, large sieve. This is exactly what you want: http://www.amazon.com/dp/B000KEJQD8/?tag=cakecentral-20

Secondly, I use my KitchenAid mixer to mix my flour, sugar, salt, and leaveners together then dump it in a bowl while I cream the butter. You can do the same if you are using a doctored cake mix - mix the cake mix and other dry ingredients with the beater paddle for 30 seconds, then add your wet ingredients.

I never sift my powdered sugar. Period.

I have never sifted cake mix. I did sift some powdered sugar once, but that was only because I had stuffed a vanilla bean in the container to make vanilla sugar. I sifted that a few times as there were some little balls, maybe from moisture from the beans. If I baked a cake from scratch, I would probably sift the flour. But I wouldn't if using cake flour. That is so light and fine that I don't think it would need to be sifted. But then, I don't really know. That is just what I would do.

And I agree, get rid of that squeeze handheld sifter! Too much work!

I sift flour if I'm baking from scratch and PS, but not my cake mix. I use a good old fashioned crank sifter and it is fantastic. I have a sieve that I use if I'm sifting a small amount like cocoa powder or making a half batch of icing, but I say crank sifter all the way!!
Here's a link to an example if you're not sure what I'm talking about: http://www.amazon.com/dp/B0017K99KO/?tag=cakecentral-20

I sift all of my cake mixes and it makes a huge difference in the way they bake and the texture. However, i don't use a crank sifter, I use a sieve and it works great. Any lumps that don't sift I break down with a small plastic scrapper by scraping against the sieve.

Thanks, everyone! I already have a seive, so I'll give that a try. So far, I haven't noticed much difference when I sift. I break up any lumps when I put stuff into the bowl, perhaps that's enough. I'll try to seive, though.