Pesky Squirrels!!!

So the other day I was refilling the washer fluid in our explorer (yes, we still have the explorer and will until it dies). Lifting up the hood I noticed it looked like something had been making a home under the hood. This is where you ask "Do you drive your car and when was the last time you looked under the hood?" Well, yes and I don't know!!!
After looking closer I discovered walnuts stashed in multiple places everywhere!!! Not only had the walnut hoarding squirrels stashed nuts everywhere but they also thought it would be a good idea to dig and tear into the insulation? from under the hood to cover their nuts. Heaven forbid other squirrels find the stash under OUR hood!?!?!?
I'm sure I picked and flicked out at least 20 or 30 walnuts!! I can imagine the squirrel(s) getting excited about finding more on the ground to bury. Maybe I should check under the hood again to make sure they didn't add to the stash!!!
Someone suggested rat poisoning but I told them I didn't want abunch of deceased squirrels around the parking lot. And I'm sure that's illegal to some extent.
Well all the walnuts are off the trees anyway and we don't plan on living in this apartment next year so that'll just have to do!