[Elecraft] What is this stuff??

[F5UL]

That is :

Tin 62%
Lead 36%
Silver 2%

Si it's safe for radio!

F5UL - Robert DROGOUL
Ref-Union - ARRL - EPC # 1952
K2 4498 - SSB - KPA100 - KAT100

Jerry wrorte :
Hey gang:

A friend drop off some solder he didn't need.     I'm having trouble 
identifying it so figured I would ask you.
Made by Kester !
Date of Man.   is      July 02
Part #             14-7150
SN62PB36AG02
Diameter is    .015
I can't find anything on the internet.    Is this stuff safe to use for 
radio ??
Just curious
Thanks and 73             Jerry    N0JRN