Can you use rubbing alcohol on your belly piercing mixed with water?

No you should be following the aftercare instructions you were provided with by your professional body piercer.

New Piercing Aftercare

1) Clean your navel piercing twice a day for the next 3 days, once in the morning and again at night. You can do this in the shower or bath but you must always rinse the piercing out using fresh running water.

1a) Shampoo, Conditioner, Soap-up and Rinse off using your normal bath products. We don't want any other cleaning or grooming products to enter a piercing we are trying to clean. Leave cleaning your navel piercing as the last thing you clean before exiting the shower or bath.

1b) Using your Soft Soap brand liquid anti-bacterial soap apply a small amount to your hand and lather it up. Once lathered, apply this to the navel piercing and jewellery, working it into the piercing by rotating the ring. Once the Soft Soap is in the piercing wait a few moments then rinse the piercing in running water again rotating the ring to ensure all the soap is out of the navel and piercing.

1c) Come out of the shower or bath and towel dry, but use a tissue to dry the navel piercing inside and out thoroughly (towels can retain bacteria and should not be used on new or fresh piercings)

After 3 Days

Follow the above steps 1a through 1c only once a day for the next three to four weeks. Between actual cleanings you may rotate the ring only under running water after you have soaped up and rinsed off and don't intend on using any other cleaning or grooming products.

After 4 Weeks

Follow the above steps 1a through 1c only once every 2 or 3 days for the next three to four months. Over cleaning is the number one cause of irritated navel piercings, striping the natural skin oils will tend to dry the navel piercing out causing it to look red and irritated.

Things Not to Do with New Navel Piercings.

Do Not use Epsom Salts, Table Salt, Betadine, Tea Tree Oil, Polysporin, Neosporin, Bacitracin, Bactroban, Bactine or any other topical solution or ointment on your piercing what so ever. These products are not for use on Puncture Wounds! If it's not listed on the above aftercare guide don't use it on the piercing!.

Do Not use Sun Block, Sun Tan Lotion, Baby Oil or any other skin care product on a new or unseasoned piercing.