EOL AP Recycling

We are starting to recycle a bunch of AP100C access points.  They were all managed by different Sophos UTMs.  Does anyone know if there is any configuration stored on these models or is it all in volatile memory?  I looked at the flashing tool article (https://support.sophos.com/support/s/article/KB-000039314?language=en_US) and it specifically says it doesn't touch the config.  I'm thinking my best option might be to connect them up, have them show as pending on the UTM, then delete from there.  Thoughts?