Hi Kemal,
I keep my W113 in my garage (a heated garage) with a soft dusk cover. A car cover is highly recommended to keep the car from getting dusty.
I got my cover from California Car Cover. It is cloth and only for dust and sun. I did not want the all-weather or moisture/water proof or resistant cover because I did not want to trap moisture and it is only a fair weather car. I wash the car cover very now and then to ensure often to ensure that trapped dirt does not act as an abrasive on the car.
I would think that a soft dust cover can be put on car just as long as the car is not wet, vice, an all-weather cover.
Cheers,
Danny
1970 280SL Siver Euro 4-speed