class Delocalize::LocalizedNumericParser

def parse(value)

through I18n. This will return a valid Ruby Numeric value (as String).
Parse numbers removing unneeded characters and replacing decimal separator 
def parse(value)
  if value.is_a?(String)
    separator = I18n.t(:'number.format.separator')
    value = value.gsub(/[^0-9\-#{separator}]/, '').gsub(separator, '.')
  end
  value
end