When you drop your person on a collectible, after they pick it up, if you pick them up, you'll still get the money.

This way you don't have to wait for them to go all the way to the office, which is especially helpful when you have multiple items in the yard, but only one kid.

I don't know if this still works if both computers are engaged.

It also doesn't matter if it's the first time you've seen that collectible, it'll appear in the collections cabinet.