When I came home for my first break I just kept the ones I wasn't wearing in my backpack shuffled in among some papers and textbooks. My mom wasn't about to open my backpack anyway, and even if she did all she would see was schoolwork. As long as you stick them somewhere where laundry normally wouldn't go (i.e. closet, dresser, on top of your bed, or if you're me on the floor), she probably won't find them. As other people suggested, hand-wash them or wash them when your parents are away or sleeping, or if you have access to a car head over to a laundromat. Or you could just amass a bunch of your white clothes and toss in the binders too (if the binders are white...just do it for whatever color). Just make sure you're the one who puts the laundry in and takes it out!
Since you mentioned you weren't out to them but want to wear a binder/packer anyway, I'm not sure if you meant you also don't want them to find out you're wearing them. Since it's winter just wear a lot of baggy/layered clothes...in the same way it sometimes works to disguise a transman's chest and diminish its appearance, it can also diminish the fact that you're binding. Layering and dressing in baggy clothes serves to hide the body and draw attention away from that region. And for the packer...tuck that sucker like nobody's business. If your parents question you on either matter, just ask them why they're looking at that particular area. Okay maybe not, just play it off and act like you don't know what they're talking about, your chest has always been this size.
Best of luck over break!
