Medal Cleaning is very personal. Some believe that they should be left as is to show the passage of time, where others want to ensure they look their best every time they are on display.
There is no correct answer, only some do's and don'ts which you should be aware of before you decide what is right for your medals.
Firstly, if your medals are showing any sign of corrosion (or 'rust'), then a deep clean will be required to remove the corrosion and treat the area so it doesn't return.
All methods of cleaning will generally require the medals to be removed from the ribbons as we utilise 'wet' cleaning methods. This is best carried out when having your medals mounted or refurbished. See here for the list of Do's & Don'ts