How much would a unopened bottle of Bols Ballerina 1575 that the music box works on it be worth?
One measure of value would be to look at closed eBay auctions: https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=bols+ballerina+bottle&_sacat=29797&LH_TitleDesc=0&_osacat=29797&_odkw=bols+ballerina+unopened&LH_Complete=1&rt=nc
but the limitation here is that all examples are going to be empty since you cannot sell liquor on eBay anymore. This is a forum for bottle collectors - the true answer you see is the bottle AND the contents so you are going to need to go out to websites that sell full vintage liquor. See my webpage for suggestions: https://www.antiquebottles-glass.com/selling-full-vintage-antique-liquor-bottles/