Well, after a raising a support ticket to BP, I received the following reply.
"I have internally queried your question right now the product does not allow you to delete or disable those fields,"
Sadly, this is another nail to Decipher's coffin as no convenient way to manage these records is available. If anyone has a template of SQL to run against reporting DB for such records, please do not hesitate to share. Also, another question, how would such action (deletion) impact the solution - are there any dependencies between removal of these fields records and level of ML models to (level of learn for OCR based on historical values and experiences) - any relations or it is safe to wipe the reporting DB out and run Decipher with same quality of models?