Now I For one happen to live with the mantra that if something can be used it should be used. Better yet if it can be re-purposed it should. At least in reason You should never repurpose your two day old balogna sandwhich.
As far as components are concerned especially for SMD. That being said it should only be the case for PROTOTYPES only. No-one and I mean NO-ONE wants repurposed components on their device no matter if it was $29.95
nor $29995. Now that that is out of the way I have pulled some fairly nice components out of what was utter trash by the time I got to it. This is an especially nice way to get components when strapped for cash on a home or hobby
project. not so much the case in a even a small devleoper. One of the tenants if you will. Know what you are looking at this means doing homework pull specs, take measurements and when it comes to electrolytic Caps I would n't.
They degrade over time and unless you own or have access to an ESR meter that can test at 100khz you cant test them properly. Besides they arent prohibitively expensive. This is only my opinion and you will have your own.
but if you are going to "scrounge" do so safely makesure all Caps are discharged, The power is disconnected. and that you know how to use what ever heat source you are going use to remove them.
Make sure you have good ventilation Pinine is toxic. Pinine is devloped from burning resin which trust me will be al over the board.
Hope this is helpful or at least enjoyable.