Clear users custom format in Google Sheets

google-script-clear-format-sheets.js

// For a SPECIFIC COLUMN
function onEdit(){
  if(e.range.columnStart === 8){ // CHANGE THE COLUMN
    var spreadsheet = SpreadsheetApp.getActive();
    var activeRange=spreadsheet.getActiveRange();
    activeRange.clearFormat();
  }
}

// =======================================================

// For a FULL RANGE
function onEdit(){
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheet = ss.getSheets()[0];
var range = sheet.getRange("A1:D10"); // CHANGE THIS RANGE
range.clearFormat();
  }