Shiva Purana
यथैव हि सुर्वणादि क्षारादेः शोधितं शुभम्॥ पूर्ववन्मूल्यतां याति तथा जीवोऽपि संस्कृतेः ॥ २५॥
When a gold alloy is purified with chemicals it regains its original value. Similarly the consecrated soul too attains purity.
english translation
yathaiva hi survaNAdi kSArAdeH zodhitaM zubham॥ pUrvavanmUlyatAM yAti tathA jIvo'pi saMskRteH ॥ 25॥
hk transliteration by Sanscript