In general, hamsters do not require grooming. Regular handling and petting your hamster will ensure that loose fur gets brushed off its body and will not result in hairballs.
Hamsters do not need bathing because they clean themselves. Bathing removes the natural oils in the hamster's coat and there is also the risk of catching a chill. Hamsters can bath in bathing sand, which can help to remove any dirt and greasiness in their coats.
The only exception seems to be the longhaired male Syrian Hamster that may require some brushing to remove dirt from its coat. This is can be done using a soft toothbrush.