core/src/main/java/org/owasp/encoder/ASCIIBits.java
ASCIIBits clear(String chars) {
        for (int i=0, n=chars.length() ; i<n ; ++i) {
            char ch = chars.charAt(i);
            if (ch < 64) {
                _lowerMask &= ~(1L << ch);
            } else {
                _upperMask &= ~(1L << ch);
            }
        }
        return this;
    }
ASCIIBits clear(String chars) {
        for (int i=0, n=chars.length() ; i<n ; ++i) {
            char ch = chars.charAt(i);
            if (ch < 64) {
                _lowerMask &= ~(1L << ch);
            } else {
                _upperMask &= ~(1L << ch);
            }
        }
        return this;
    }
Clears the bit (sets to 0) for each character in the argument string.

@param chars the characters to clear.
@return {@code this}