You try to redeem them and keep track of the mints where you can clear to a Lightning payment.
Discussion
You are also signaling from the start the mints you want ecash on, so you could even just ignore mints you don’t want, or yeah, like nostr:npub1q6mcr8tlr3l4gus3sfnw6772s7zae6hqncmw5wj27ejud5wcxf7q0nx7d5 says, you try to redeem and ignore the mints that dont work