[QUOTE=imas560]...Was thinking it might be able to go into the pineapple juice process...QUOTE]
Please, no pineapple juice on a mandau

. Its not a keris..
And this blade looks still very good. clean it with 00 or 0000 steelwool and a little bit of oil. I am sure that you will be satisfied with the overall appearance.
The stone is a later addition. I recommend to remove the remaining one also if possible.
As for the origin. kayan/kenyah south east Borneo
Correct me if someone has a better or more specific view on that.
Age : early 20th century (again imho)
Best regards,
Willem