### Clue: Collective elements of a party elite fighting to infiltrate extremists in tribe (10)
### Answer: TUPPERWARE 
 ### Explanation: Definition: Collective elements of a party
 [ UPPER(the elite) + WAR(fighting) ] **contained in**(to infiltrate) **the 1st and last letters of**(extremists in) "tribe ".
Defn: Collectively, the items sold at "parties" described by the trademark brand.