The problem is that once the grease reaches a cooler section of the plumbing, it can solidify again.
Instead of eliminating the grease, you may simply move the problem deeper into the pipe.
Over time, accumulated grease can contribute to slow drainage and blockages.
Never Pour Cooking Oil Down the Drain
The better rule is simple:
Don’t intentionally dispose of cooking oil or large amounts of grease through your sink.
Let used cooking oil cool and collect it in a suitable container for disposal or recycling according to local guidelines.
For pans containing a small amount of grease, wipe them with paper towels before washing when appropriate.
This can prevent a surprising amount of grease from entering your plumbing.
Does Hot Water Ever Help a Drain?
Yes.
Warm or hot tap water can be useful when cleaning dishes and may help wash away small amounts of residue.
The issue is the extreme temperature and quantity of water.
There is a major difference between washing dishes with hot tap water and dumping a large pot of freshly boiling water into a drain.
What About Salt, Baking Soda, or Vinegar?
Home remedies involving baking soda, vinegar, salt, or boiling water are popular online.