With all due respect to his brilliance one is allowed to have a drink with a lemon wedge in a non-kosher bar without any issue whatsoever. A lemon is considered a “Dovor Charif” (sharp item) and when a non-kosher knife is used to cut the lemons the first lemon attains the status of non-kosher from the knife thereby rendering all other lemons cut as having being “kosher” with regards to the first lemon they are generally placed in a bucket to be used during the entire day and the first lemon would most prob be “botul beshisshim”
Sorry, that makes no sense. You aren’t even using terms correctly. You mean batul b’rov.