What are the medications you are taking?
The amoxycillin and Clavulinic acid combination can be responsible for the this salty taste in phlegm. The other reason for this are;
1) Associated gastroesophageal reflux disease
2) Infective organism
This is usually self limiting / self resolving and may not require any treatment.
Please feel free for your follow up questions.
Medicines get out of our system in 72 hours, so after this it should be normal. As I mentioned, concomitant illness or factors can also play role like, GERD or sinusitis.
It is pleasure and privilege assisting you.
I hope this was helpful to you. If it was, please remember to ACCEPT the answer so I can get compensated for my work. if you have any more questions, please feel free to ask. I am truly privileged to help you, and I want to make sure that you are satisfied with the answer. Good luck!