Slabbing is the word for companyies that grade chips/coins and enclose them in a sealed holder. Archie Black wrote a great article here

http://slabfree.marlowcasinochips.com/whybeslabfree.htm

Although I do have have a number of slabbed coins in my COIN collection, the slabbing of chips is an all around bad idea at this time based on the size and limited scope of the Chip collecting community.