thx for the additional information, dazza, it sure helped a lot
! i've ordered a couple of sprays in the meantime and once they arrive (along with a desoldering station) i can finish what i started today!
the card edge wires came off easily, but as you can see there is still a lot of flux and solder on it (the soldering job wasn't the best to begin with). i only heated up the older solder to get the wires off and did no additional cleaning because i didn't want to damage anything, i'm waiting for the rest of the stuff to arrive.
much worse was the connector on the left, because the wires had been wrapped around the pins multiple times and huge solder chunks had been added. it took me quite a while to get everything off, but i think it cleaned up ok, but i'll have to re-work it as well!
here's what i removed from the connectors