Strange but true.
I've seen auto and lawn tractor Batteries accidently charged up reverse polarity.
I've had to install a load such as a lamp bulb or headlight and drain/discharge them completely and sometimes re-charging with correct polarity they will be ok for a while, but it usually shortens their life or seems to reduce their CCA.
When re-charging to correct polarity I usually have to use a manually adjustable rate battery charger so as to keep the amps around 2 amps or less. A automatic type battery charger usually will not start the charge on a completely dead battery and the charge rate needs to be held to 2 amps or less until the battery is fully charged.
Summary: Usually best to just replace the battery.
I've seen auto and lawn tractor Batteries accidently charged up reverse polarity.
I've had to install a load such as a lamp bulb or headlight and drain/discharge them completely and sometimes re-charging with correct polarity they will be ok for a while, but it usually shortens their life or seems to reduce their CCA.
When re-charging to correct polarity I usually have to use a manually adjustable rate battery charger so as to keep the amps around 2 amps or less. A automatic type battery charger usually will not start the charge on a completely dead battery and the charge rate needs to be held to 2 amps or less until the battery is fully charged.
Summary: Usually best to just replace the battery.