String sanitizer for MySQL's default utf8 encoding - You can avoid needing to use this by switching to utf8mb4

mysql_string_sanitizer.rb

class MysqlStringSanitizer
  def self.sanitize(str)
    str = str.force_encoding('utf-8').encode
    clean_text = ""

    # emoticons  1F601 - 1F64F
    regex = /[\u{1f600}-\u{1f64f}]/
    clean_text = str.gsub regex, ''

    #dingbats 2702 - 27B0
    regex = /[\u{2702}-\u{27b0}]/
    clean_text = clean_text.gsub regex, ''

    # transport/map symbols
    regex = /[\u{1f680}-\u{1f6ff}]/
    clean_text = clean_text.gsub regex, ''

    # enclosed chars  24C2 - 4DFF
    regex = /[\u{24C2}-\u{4DFF}]/
    clean_text = clean_text.gsub regex, ''

    # more enclosed chars  24C2 - 1F251
    regex = /[\u{A000}-\u{1F251}]/
    clean_text = clean_text.gsub regex, ''

    # symbols & pics
    regex = /[\u{1f300}-\u{1f5ff}]/
    clean_text = clean_text.gsub regex, ''

    # supplemental symbols & pictographs
    regex = /[\u{1f900}-\u{1f9ff}]/
    clean_text = clean_text.gsub regex, ''
  end
end