as you are taking thyroid
medication for 10 years now you have salty taste in mouth .
for salty taste in mouth there are many reasons and one among them is side effect of certain therapy such as antithyroid and chemotherapy
in your case it is side effect of thyroid medication kindly meet your and discuss the matter if your taste for thyroid is negative then you can stop the medication slowly and as homeopath
i can suggest to meet some classical homeopath who can help you in curing your complain.