When any forfeited lands are repurchased, as provided for in sections 282.241 to 282.324, no structure, minerals, sand, gravel, topsoil, subsoil, or peat shall be removed, nor shall any timber or timber products be cut and removed until the purchase price has been paid in full. Nothing in this section shall be construed as prohibiting the removal of such sand, gravel, topsoil, subsoil, or peat as may be incidental to the erection of structures on such repurchased lands or to the grading of such lands whenever such removal or grading shall result in enhancing the value thereof.