import re


def rmchars(value):
    """Remove special characters from alphanumeric values except for period (.)
    and negative (-) characters.

    :param value: Alphanumeric value
    :type value: string
    :returns: Alphanumeric value stripped of any special characters
    :rtype: string

    >>> import utils
    >>> utils.rmchars(value = "*6.5_")
    '6.5'
    >>> utils.rmchars(value = "ICE")
    'ICE'
    >>> utils.rmchars(value = "-4.2")
    '-4.2'
    >>> utils.rmchars(value = "%&!@#8.32&#*;")
    '8.32'
    """
    value = re.sub("[^A-Za-z0-9.-]+", "", value)
    return value