![Clean Columns 1 Clean Columns](https://excel.civilmdc.com/wp-content/uploads/2021/10/Clean-Columns.png)
After a run, the column is simply washed with 2-3 column volumes of the initial solvent mixture before starting a new separation. However, some impurities that are strongly retained on the column will accumulate at the intlet, if the mobile-phase composition is not strong enough to elute them during a regular run