Even though your instrument is made of metal and looks solid, please remember that it's very fragile! Some antique bowls have such a thin bottom that you can hear a clicking sound or even make a hole if you press it with a finger. Always put the bowl on something soft, such as a rubber shelf liner that we also provide. If you put a bowl on a wooden surface, check that this surface is totally flat with no nails sticking out or any other firm particles. Always be gentle with your instrument. Don't strike too hard with the firm mallet and even if the mallet is soft, still consider that the wall could be very thin and your approach could be critical for the bowl.
If you decide to clean the bowl, it's up to you which method to use, but please remember that using abrasive materials such as sand paper could influence the sound of your bowl. Traditional method to clean brass made bowl is polishing it with a paste made of squeezed lemon with wooden ash (the ash could be replaced with the baking soda). Make this mixture using approximately 50/50 lemon juice with pulp and ash, and polish the bowl using a soft cloth.
Any polishing paste for cleaning jewelry will do the job. Make your preference for a copper polishing paste.
Storing the bowls like a Russian dolls (one inside another) could be fatal if there is no soft gasket in between the bowl's surfaces and there is too much weight.If you store it this way, put the bottom bowl on something soft and use rubber O-rings or rubber shelve liners in between. Don't put stack too many bowls one inside the other. If you have any question on how to safely store and maintain your bowls, just contact us and we will be happy to advise you on this!