This might be in another (similar) field. This danish coin from 1897 had a catalog value of 1.000 danish KR corresponding to 180 USD.

Then it was made into a charm thereby destroying the coin and it value for a numismatist.
In this case a bowl from 1911.

When I first saw this it had an engravement from the 1930s - someone had had this as a gift. I did not buy it - the price was too high. But later they had a sale and the price was reduced by 30% so I bought it. Their idea was that owners initias etc was spoiling the sale of such a piece - I do not agree. I know that I am not the original owner and i think that we should respect that others have had things before us.
In case that owners initials are from 1700 - we all agree that they should remain. But is that also the case when you have a piece from 1900 and a 1900 owners initials? I am sure that people in 150 years from now will regret that this 1930s engravement has been removed.
We also see coins used as decoration on silver pieces. Around 1900 a lot fake antique silver was produced pretending to be 1600 and 1700. To make these pieces look real, they used original 1700 danish coins. Thereby destroying them as a coin and making them worthless. Today some of these coins represent (as a coin) a higher value compared to the whole item as a silver piece - but destroyed as they are - no value at all.
I have presented this piece before

It is the bottom of a danish (i think the english word is) beaker. It contains 4 hallmarks. 3 of these Guardein, City and Monthmark are reused from a piece from late 1700 when he made the beaker i 1849 he reused parts of an old piece - added his mark - and saved taxes because he reused the hallmarks. At that time it was a criminal thing to do. Today it brings life to my beaker - gives it a unique history, and is funny.
So we find it good. They considered it bad.
Lots of table silver spoons, forks etc. contains original owners initials. These are easy to remove and put in your own - should we do so?
well for practical reasons it good - you get you own silver. You also destroy the history, but we do not live in a museum. however do people in next century have the same opinion?
I have lots of silver with original owners initials, later owners have added their initials. In that case you can follow table silver from generation to generation. From owner to owner. I find that positive.
In same aspect am I "alowed" to put my initials on a 1700 piece? I think yes - but I should do it in respect of the old thing and the old initials. I should not destroy it with my engraving. But as the present owner I have the same right as the original.
We find it not OK to change things - 100 yeas after it was made. We like to have things as original as possible. We should bear in mind that it is not museums pieces we change. its things that we use on daily basis. It things that we have bought for a small sum - others similar exists. So perhaps its OK to make it look the way we want. But please do not destry it.
This became very long and it does not follow the original question, but I found that it was an aspect of the same question - another angle. Worthy to comment upon.
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