Re: cleaning the inside of a purchased used saxophone
Usually an used saxophone need some work. Partial or complete repad, springs adjust, cork regulations and a cleaning is generally included, so I suggest you to contact a good and honest techinician.
But, for me, the matter is another.
If you are interested for a student model saxophone maybe is better that you buy a brand new horn, otherwise compare well the price of the used saxophone with the cost of the overhaul.
However to clean the outside of the sax you can use Sterisol germicide.
To clean inside use a cotton swab, better made by yourself because it must to pass tightly.
Damp with water and soap, pass more times. After with water only, then dry and pass a swab LIGHTLY imbued with bore oil