The only way to properly update your list is to accomplish two things:

1 Add the new chips
2.Delete the chips that are gone.

This means you have to go through all of your trader chips and mark it as "in" in some fashion.

This is somethingwe all have to do. Whats really bad is when you go through it and still miss a couple (like I did). I just was doing a trade with Jill and discovered I didnt have one of the chip she had slected any longer. This is something we all experience, and all understand, but it's still embarassing, not to mention the extra emails and time involved with completing the trade.

It sounds like what youre doing is about the best. Of course....you could always use a bar code for each chip and then use a bar code scanner. Hmmmmmmm. kinda makes ya think doesnt it!