Why would dice be “retired” from a Casino floor? (ebay.ca)

I know that dice can be manipulated. I have read about a technique where dice can be put in the oven somewhere around 200 degrees with the intended values up to change the weight distribution and effect the probability without outwardly noticeable characteristics. Every time a player touches a die there is likely a possibility of them switching them with loaded replacements. Perhaps changing dice is a way to mitigate that risk.

Some casinos sell some retired dice with holes drilled through them as souvenirs. They retain a good-enough balance for casual play.

Here is a link I found by searching 'dice holes drilled'. It goes into more detail about the 'why' of retirement than I know about.(https://www.goodgamblingsites.com/articles/why-do-casinos-dr...)