Question the design of your spin column. All spin columns are not created equal, and designs from some other companies may result in buffer retention, even after centrifugation. The buffer carry-over can contain high concentrations of salts, detergents, and other buffer components that are eventually eluted from the column along with your DNA or RNA samples. This contamination can inhibit many types of downstream applications, and is an especially big issue for sensitive techniques like Next-Generation Sequencing and bisulfite conversion.
The Zymo-Spin columns used by Zymo Research in their DNA and RNA purification kits, including their EZ DNA Methylation line of bisulfite conversion kits, are specifically designed and engineered to ensure the quality of your samples by completely eliminating buffer carry-over and allowing elution of extremely pure DNA and RNA in low volumes. Zymo Research explains all about the design of their Zymo-Spin columns in the video below:
The Zymo-Spin column technology is featured in numerous Zymo Research products, including the DNA Clean & Concentator™ (DCC™) and other DNA clean-up and isolation kits.