The kad-indriya, or unpurified senses, can be purified if one engages the senses and the mind in Krsna consciousness. Sarvopadhi-vinirmuktam tat-paratvena nirmalam [Cc. Madhya 19.170]. One must be freed from all designations. When one identifies himself with the material world, his senses are impure. But when one achieves spiritual realization and identifies himself as a servant of the Lord, his senses are purified immediately. Engagement of the purified senses in the service of the Lord is called bhakti. Hrsikena hrsikesa-sevanam bhaktir ucyate. One may enjoy the senses for many thousands of years, but unless one purifies the senses, one cannot be happy.