Tirukkural-On Virtue-On Rectitude-Kural 113

Even if it can be put to good use, wealth acquired by unfair means,Is best renounced all at once.

Only the wealth earned by fair means will be productive of good; all other wealth, which one comes by through questionable means, can only produce evil.

This idea that such ill-gotten wealth is an inimical burden both in this life and the next, finds mention in Kalithogai.

Semaiyin ekanthoari epporul seivaarkap porul
Immaiyum marumaiyum pagaiyaava thariyaayo

It is, therefore, proper to renounce it all immediately, without looking for the doubtful satisfactions of even good use of ill-gotten wealth. one is reminded in this context of the attempt of some to purify black money by sharing a moiety of it with the Temple coffers. In recent times special bearer bonds have provided official regularization for black money.