Even if you used lead free solder, you would not be lead free. After
all, your component leads and your printed circuit boards use tin/lead
solder to insure solderability. Until all of the components are lead
free, you will be chasing smoke. this is especially true when repairing
old electronics.

If you use a non-lead solder with leaded components, you will most
likely creat brittle intermetallics which will greatly reduce the
reliability of your equipment. The biggest problem to date is the
intermixing of various solder compostions. Uncontrolled mixtures with
unknown properties are created.

Yes, I know, there are lead free leaded components. For example, gold
plated leads on ICs. But, these do create brittle intermetallics if the
solering process is not exact. And I doubt it is exact when using a
soldering iron.

A few years ago, I worked in a lab where we evaluated various solders
for our customers. Things may have changed since then, but believe me,
you don't want to do it yet.
====================================
Considering the above , I shall stock up with solder currently available eg
with lead.
Even when it is stated (in another message earlier in this thread) that only
'fresh' rosin core solder will give the best results.

Frank GM0CSZ /KN6WH located in EU