How do I spend Bittrex credits?

Can you tell me how I can utilize the credits I have accumulated on Bittrex? Are there specific steps I should follow to spend these credits? Are there any restrictions or limitations on how I can use them? Are there any fees associated with spending my Bittrex credits? Is there a list of merchants or services that accept these credits as a form of payment? Additionally, are there any tips or best practices you could recommend for maximizing the value of my Bittrex credits?