Every cyclist can do something to prevent rust, salt water corrosion, icy technology and mud deposits in winter. If you look after and protect your bike in advance, you will have far less trouble in the spring. Winter has an aggressive effect on the bike and all its parts.
However, protective and care products are only effective if they are applied to clean surfaces. Step 1 is therefore: Wash thoroughly. Spray plenty of bike cleaner (biodegradable) onto the frame, drive unit, wheels and tyres and leave the substance to work for a few minutes. Then wash with a hose or bucket, brushes and a sponge. Please refrain from using a high-pressure cleaner: the sharp jet of water removes too much internal lubrication from the headset, bottom bracket and chain links. Afterwards, wipe all surfaces dry with an absorbent cloth so that only loosened dirt does not dry again and no marks are left.
Special bicycle degreaser sprays are suitable for the chain and drive or, better and cheaper, a cloth soaked in petrol. Crank the chain through the cloth until the chain and sprockets are superficially clean. Do not use fillable chain cleaning devices. They wash too much lubricant out of the chain links.
As a protective layer, use frame polish for painted surfaces, care oil and finally liquid or spray wax for all other surfaces such as screw heads, brake lever or gear lever mechanism, but also drive or spokes. Treat drive belts with silicone spray. This prevents or at least reduces the adhesion of dirt, but also of slush or ice. Tiptops Bike Fluid does a similar job on the sprocket set, Bowden cables and lock. Always make sure to keep brake flanks, pads and discs free of grease!