Seams are glued with a water soluble glue that allows the instrument to open at the seams rather than crack. Only the style and choice of music. Occasionally, fiddlers prefer a slightly flatter bridge and steel strings to gut or perlon. Otherwise, the instruments are exactly the same. There are many cleaners and polishes on the market.
Most instruments only require a careful wipe with a cloth after playing.
Be careful not to use alcohol or oils to clean without first consulting with a trusted maker or repairperson. Treat your instrument the way you would a child. Do not leave it unattended in a hot or cold car. Look closely under good natural light at the suspected area. Try inserting a business card into the suspected area.