Removing a chip with hot air and tweezers can be a bit awkward.
Tying a 30 AWG wire around one of the pins, makes things a bit easier to manage.
Slightly pull on the wire as you evenly heat the pins on your device.
When all the solder melts, remove the chip.
Works well with larger chips, #7.
Of course your chip has to have legs, this will not work on QFNs etc.
Neat trick, I can see the reason for it. The tweezers will get quite hot if they are anywhere near the chip when you are heating it. I leave the tweezers aside and don't touch the chip with them to lift it up until I have melted the solder. There's about a 3 second window to pick it up after melting the solder before the solder starts to solidify so the chip comes up without sticking.
Option #2
You can tie the wire at opposite corners to get a loop.
Attach the center of the loop to a stretched elastic band.
Heating now results in pulling the chip off automatically when things melt.
This helps free one hand.
Both methods work well.
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I had to rework about 20 CPU boards due to a flow solder process error resolting in all the CPU chips
( 100 pins ?) missing solder on several pins.
I thought you were retired.
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Just thinking, a vacuum pickup to the center of a chip with elastic pulling on the hose might solve the QFN outlier.
Something like this but the vacuum hose would be supported by a stretched elastic.
I made a tool as shown here, it works great.
I'll have to try this with the hot air iron on some snowy day 
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I thought you were retired.
That was quite a long time ago (at a different company) but I going to work till I'm 70 (if possible)
I just poke it with a stick. Seems to work (and its a fine pointed tool more than a stick to be fair)
The vacuum pickup tool is a clever idea Larry.
Another trick is "low melt" solder. As you heat it up you can add a bead of low temperature solder (covering and "shorting" all of the leads). Somewhow, the liquid low-melt solder mixes with the existing solder at it all liquefies at a lower temperature. You are left with lots of solder on the board which is easy to suck-up and clean off, but the globs of extra solder on the IC can be difficult to remove and can make it non-reusable (but you probably didn't want to save it anyway).
You don't need to solder with the low-melt solder, just use it to help with the de-soldering.
Where I used to work we had a [u]Zephertronics[/u] rework station and I could usually remove a chip with just the pre-heater and low-melt solder. (I could remove any chip but was NOT good at soldering-in the replacement chip if it was fine-pitched.)
