I know unused denominations are automatically removed by the system (the Numista Robot). https://en.numista.com/forum/topic153824.html#p1207089
Numista has other database entities: https://en.numista.com/help/guidelines-for-the-numista-catalogue-141.html
Which of these are also automatically removed by the system if they are not used for a while? I ask for this to avoid do unnecessary requests.