View difference between Paste ID: vVasrXy1 and J4FeRTBF

 function acraCleanup() {
   var SPREADSHEET_KEY = "BBBBBV9AAAAAAGJGZVQ0Z2M0WnFDSAFAGACWFUMUE";
 
 // Replace with your spreadsheet Key,
 
 //you can find this by trying to share the Spread sheet
 
 // and getting the key between the "=" and the "&"
-  var SHEET_NAME = "Sheet 1"; //Sheet 1 unless you changed sheet name
+  var SHEET_NAME = "Sheet1"; //Sheet1 unless you changed sheet name
   var rowsToKeep = 1000; //Will keep bottom 1000 Rows
   var sheet  = SpreadsheetApp.openById(SPREADSHEET_KEY).getSheetByName(SHEET_NAME);
   var rows = sheet.getLastRow();
   var numToDelete = rows - rowsToKeep - 1;
   if (numToDelete > 0) sheet.deleteRows(2, numToDelete);
 }