The approach on rejuvenating your floor initally depends if the original floor was machine polished or if it was a grind and seal job.
If the floor was sealed then a new grind and seal (or machine polish upgrade) will probably be in order.
If the floor was machine polished then provided harsh cleaners have never been used on the floor it might be possible buff the floor back up as the dullness might be caused by oils and contaminants or dirt on the floor.
If harsh cleaners, especially citrus based cleaners have been used over a period time you can definitely permanently lose the shine of a machine polished floor. To rectify this a re-polish might work however depending on the nature of your individual floor the treatment may be different so a consultation will be necessary.
Your very best bet is to try and wash the floor several times with hot water and a neutral floor cleaner like GTA Tough Green Cleaner.
Please also check the maintenance sheets on our website for more detailed cleaning information.
Hope this helps! If you need additional assistance please contact us.