The iRobot battery terminal is covered with “salt” after inactivity, is it safe to use?

Question

Batteries

The iRobot Roomba 880 robot vacuum cleaner stood unused for a long time with a battery inside (contrary to the recommendations of the instructions to remove the battery when idle for a long time).
During an attempt to charge it, he issued an Error 5 . I removed the battery and found that one of the terminals was darkened and covered with white salt-like crystals.
Can I clean the terminal, return the battery to the device and try to charge it, or will it damage the robot?
Battery information:
Advanced Ni-MH Battery
model: iRobot XLife™ Extended Life Battery
DC 14.4V 3000mAh Ni-MH

Answer 1

This is called "drip" - the electrolyte leaked out and dried up. The use of a current battery is not recommended as its performance is no longer as advertised.