Exported email lists, copied spreadsheets and pasted logs all arrive with duplicates, blanks and stray whitespace. Paste the list, check the cleanup options you need, and get a clean result with a before/after count.
What each option does
Remove duplicate lines keeps only the first occurrence of each line. Keep original order avoids reshuffling your list alphabetically. Remove blank lines drops empty or whitespace-only lines. Trim edges strips spaces and tabs from both ends of every line. Remove all spaces strips them inside the line too — useful for phone numbers and IDs.
Practical notes
Matching is exact and case-sensitive: "John@mail.com" and "john@mail.com" are different lines. If you need case-insensitive dedupe, convert the text to lowercase with the Case Converter first, dedupe, then restore. Very large lists (hundreds of thousands of lines) are still fast — the logic is a hash set.