Read about real people, real forensic facts & truths, versus the safety of drain cleaners and/or drain openers.  These truths about the dangers, pipe damage, and human dis-figuration can be seen here at:

Drain Cleaner – Cheap but *read this*

Many homeowners have used a crystal or liquid drain cleaner or drain opener.  There are many brand names.  Many of us have found we had to replace the drain trap after using one of these products as it continues to aggressively eat through plumbing parts, eg: a bathroom vanity drain trap.

Although a vanity drain trap is visible and easily replaced, it is a hidden cost.  What is more hidden though is the damage done to your plumbing in hidden areas that you do not see.  The forensic photo found on the page listed above shows that chemical deterioration continues to occur to a drain pipe sewage system even though the drain cleaner / drain opener was used 4 days prior.

So do not use drain cleaners or drain openers if you have frozen pipes.  Some people call it thaw or thawing or unthaw or unthawing or even unfreezing a frozen pipe.  If you are wondering how to D.I.Y. (do it yourself) and what to safely use to thaw your frozen water intake pipes or well pipes, your drains, sewers, septic system lines and tanks, then you have just found the ONLY safe solution other than good fortune and luck or a plumber.

So for your personal safety as well as to prevent deterioration of your drains, sewers, septic pipes, septic tanks, and septic system line it is therefore recommended that you consider using other safe alternatives.

On days when the weather is freezing outside and your underground pipes and some pipes in your walls are exposed to the frigid cold of winter, it is a good practice to open cupboard doors and run some hot water before calling it a night.