Here's what you do.
Boil a small pot of water on the stove, and dip the cap part of the Swiffer Wet Jet bottle into the water for about 90 seconds. Then simply twist the cap off. The heat helps soften the plastic enough so you can just give it a good twist and it will come right off. But make sure to use a towel or something because that cap gets pretty hot.
The cap has these little flaps inside that catch on the bottle so that you can't open it again. Your next step is to cut those off. The article I read says to use a finger nail clipper to just snip them off. I actually made James do this part. Well, I didn't so much make him, as he just took over this part. He loves stuff like this. He said a sharp knife and a steady hand worked way better than a finger nail clipper. Anyway, now you can screw and unscrew the cap at your leisure - no boiling required!
I decided to use my favorite all-purpose cleaner. I'm pretty much in love with Mrs Meyer's basil scented stuff. It smells so fresh and wonderful! And this bottle is super cost-effective. It's about $8, and it's concentrated, so 1/4 cup makes a gallon of cleaner. This bottle lasts a looong time.
So I mixed up a half gallon of my favorite basil scented cleaner and I refilled my Wet Jet! I was SO super happy about finding out this wonderful little tidbit. I really like my Wet Jet, and the fact that I can now use it with my favorite kind of cleaner (that's more healthy for my dog and my kids) really got me excited. I know, that's pathetic, but I try to find joy in the little things. :)
Aaaaand, I had some cleaner left over, so I poured it into a handy little spray bottle. I only have a little bit left of the all-purpose cleaner I keep in the bathroom, so this will be a great replacement for that.