I wish I'd read Christa's comment beforehand. I didn't and started the process just fine, then both strips broke. I used a hairdryer multiple times to make progress melting the strips and wedging out the battery. Using a credit card alone (and then a credit card plus floss) wasn't enough. I used a cheese knife (carefully) for more leverage and that made the difference.
I skipped those steps too and was successful. Thanks for this tip!