How Renew Components Cleaned Tin ???

[Alx]

Have you ever noticed electronic Renew components such as ICs and transistors?
The Pin IC and transistors tin is completely cleaned.
  It looks like it has never been soldered before.
   my question is. How is this done? Is there a specific solvent?

[ataradov]

Yes, this happens a lot, especially to power transistors. Sometimes you even see legs that are extended and it is not very noticeable without  examination.

Given that stock ICs are coated, there must be industrial machines for that. In a less industrial environments, I've seen people dip the IC into a solder bath and use air gun to blow away the excess. But this is only viable if labor is virtually free and components are expensive.

[abdulbadii]

On its standalone, (some of) its pins heated to molten the minute tin remnant and immediately wiped/applied with near-strong acid damped clothe and brush with very fine metal brush or sandpaper and immediately cleaned/wiped out with IPA damped clothe