how to clean the memory termed as 'others' in iphone 4s
Not quite sure what you mean. Most of the items labeled as ‘Others' are documents or info created by your Apps and can’t be deleted,  but you could try installing the (free) Battery Doctor app and running the memory boost and junk purge programs.

If this fails, back up (ESSENTIAL) and Settings>General>Reset>Erase all content and settings, then either reinstall your backup, or start as a new device and add apps one by one, starting with the most important. If you follow the latter course, make sure you screen grab and email or note down your network settings before resetting !