Just stick'em on the shelf 'til spring, and build a couple more in the meantime.

I've never stored (read: not flown) one for more than a month. If you're a fan of after-run oil, just lube up the engines good, and then cycle your batteries when you get ready to fly again. Not much else to worry about, unless you've got termites.

My oldest engine is 4 years old (.65 Saito), never had after-run oil in it, and runs as good as the day it was new. My planes all stay in my garage, gets as hot as low 90's in summer, as cold as high 40's in winter, and I don't take any special pains with them.