Awesome trick with Bi58Sn42 - when desoldering really heavy, “heatsinky” stuff, such as connectors, turret terminals etc - melt some 63/37 into factory lead-free joints and then mix in Bi58Sn42.
Lead-free melts around 210-230, 63/37 at 183, Bi58Sn42 at 138, but Bi-Sn-Pb you just melted together can melt as low as 90C, depending on the exact mix.
(Similar trick like 63-37 to begin with - lead melting point 327, tin 232, mix them together and voila - 183C)
Btw, yea - I also use bismuth only for desoldering. It’s a neat trick to avoid mess.