Cleaning of the Cello
When cleaning a cello, it is important to always keep the safety of the cello in mind. Never use any type of cleaner that is alcohol based because it can remove the varnish on the instrument, as well as make sure you aren't rubbing too hard, nor nearly not effectively cleaning the cello. A soft felt cloth is the best item to use to clean a cello, or any other strings instrument.
When done playing it is always recommended to rub down the cello to get the dust and rosin off the cello. As always, it is a good practice to keep the cello in a case to protect it. Storing it away will help keep it clean and healthy.
If questioning types of cleaner or methods, the best thing to do is contact your local violin shop and ask them for advice, or consult a trusted teacher or professional who has experience with instruments.