desoldering trick?

[madires]

I don't know if this is widely known or not, but when desoldering components many add additional solder to help with the desoldering process, i.e. for a better heat transfer and to break any oxide layers. From my experience it is the flux core in the solder what helps, not so much the solder. So you can simply add flux to the solder joints before desoldering the component and won't wasting solder. A simple flux made from colophony and IPA works fine. Works also great with a desoldering gun/station. For really crusty joints you still might have to add a little bit solder.

[mariush]

Lead free solder melts at 217c
Lead based solder melts at 180..183c
Low melt solder melts at even lower temperature.

The added solder can mix with the existing lead free solder, lowering the melting temperature so it can help if you use a desoldering wick or solder sucker to take off the solder off a larger surface with less risk of damaging surfaces due to too much heat applied...

Yeah, the flux in the solder core or additional flux helps break the oxides, but the added solder also helps by increasing the contact area between your soldering iron tip and the pad/lead you touch with your soldering iron.  More heat is transferred from your tip to the area with solder.