It's that time of year when skis need to go into hibernation.
I know. It's sad.
You could be lazy and throw them in the basement for the bases to collect dust and oxidize slowly over the summer, or you can do the right thing and apply storage wax to keep them protected and extend the life and performance of your skis.
You'll need a waxing iron, profile, scraper, wax remover, and a soft glide wax. Universal or warm waxes work well.
Step 1: Clean the bases (classic skis)
Scrape all the goop you can off your kick zone. Apply a little wax remover and use Fiberlene or a cloth to get anything sticky off of there. You won't be covering this area with glide wax but you don't want it attracting dust (pet hair.. dryer lint.. dead bugs.. etc) while in storage.
Step 2: Apply your wax
Wax your skis as you usually do and iron it in. Don't scrape it however. The idea is the wax seals the bases so nothing can get at them. Just wax the glide zone(s): tip and tail for classic skis, the entire ski for skate skis.
Step 3: Store your skis in a safe place
You can store your skis horizontally or vertically. Some people use shelf brackets on the wall for this. Putting them in a ski bag will further protect them, but isn't necessary.
When you're ready to start skiing again, simply scrape off the storage wax and give the bases a good brushing with a copper brush. Then hot wax your skis for the conditions and you are ready to go!