How can a neutral body be charged electrically?

(N/A) To electrify a neutral body,we need to add or remove one kind of charge.
$A$ body can be charged positively by losing some of its electrons. Similarly,a body can be charged negatively by gaining electrons.
The body that loses electrons experiences a slight decrease in mass,while the body that gains electrons experiences a slight increase in mass.
When we rub a glass rod with silk,some electrons from the rod are transferred to the silk cloth. Thus,the rod becomes positively charged and the silk becomes negatively charged.
No new charge is created in the process of rubbing; charge is only redistributed.