Yeah... I'd even go more drastic than Stush is recommending, chop it off and re-root it - the places that have completely lost the leaves won't get them back again, and the leaves that have been browned at the tips won't regenerate either; I'd carefully trim the brown off with very clean pair of scissors. But it definitely needs a soapy shower, thorough rinsing and probably just a lot of TLC.
If I remember correctly, they're pretty low-light plants, so I wouldn't put it in any direct sun, but something fairly bright would probably be best.
