What you need:

• Scavenger Perk
  
• Care Package Killstreak
  
• Semtex Grenade

1. What your going to do is get a care package killstreak.

2. Once you have your care package - throw a semtex towards an enemy, and right when it blows up - pull out your care package

3. Throw your care package and if you did it correctly - you should have another one after you throw it.

4. If you actually want unlimited care packages - every time you kill the enemy with the care package - pick up his scavenger bag to refill ammo - then repeat steps 1-3

If you want to do this - remember there's always a risk of being banned / reset for boosting... because this is a way of boosting. You get care package points and you get points if the killstreak in the care package gets kills, so be careful when glitching.