Throughout the season, dirt will have accumulated under the base of the skis, that's why you cannot store them in this condition.
It is important to clean them and protect them before storing them in the best conditions.
PART 1 - CLEANING
After you last outing, dry your equipment.
Dry your skis with a microfibre cloth to avoid damp infiltrating your skis, especially the base, as well as the top and bindings.
Perhaps you don't know this but damp is the enemy of your skis. That's why drying it after each outing is crucial.
Are your skis dry? You can move on to the next stage. You must now remove the wax from the bases.
1 - Remove the wax from the base by applying a wax remover or fluoride cleaner using a cloth on the base of your skis.
Warning, on classic cross-country skis, use the wax remover only on the grip area, not on the entire base.
Some wax removers are made using natural products, sometimes citrus fruit, that are not harmful to the environment.
2 - Then dry the bases with a cloth. If some parts or the "edges" are damaged, you can use a metal scraper to smooth or erase imperfections.
PART 2 - PROTECT
You can now protect the base of your skis by applying a thick coat of wax. This layer will protect your skis in two ways: the wax will nourish the base and it will protect it from the damp.
1 - Brush the base of the skis with a nylon brush from the tip to the heel
2 - Set the temperature of your wax iron as recommended on the package of your wax.
2 - Apply the slide wax in a thick and even layer using your iron. To do this, apply the wax in a constant tip to heel movement. Unlike a pre-outing wax job, leave the extra wax on the skis. Be careful: On a classic cross-country ski, do not wax the area designed for grip wax.
If you do not have the necessary equipment for wax removal and waxing, you can have it done by a professional.
PART 3 - STORAGE
Once the wax is in place, attach your skis using a ski tie without over-tightening to stop the bases from touching each other. Allow sufficient space for the original camber of the ski to be respected. You can then store your skis in a clean and dry storage case. Then store them in a dry place with a stable temperature, below 20°, far from light and heat. Be careful of garages and cellars that are either subject to temperature variations or are too damp.