Advice regarding disposal of 50?

Question

Dear Sir Since nobody is picking up the telephone at the nos. mentioned for your customer care division I am forced to send you a mail on the above subject. I am having a substantial no. of 50 paise and 25 paise coins which are not in circulation. Request to advice that whether these can be exchanged or simply be sold as scrap.
Yours sincerely
Hiranmay Ray