the real way to go is have a rogue & someone with detect magic check it out first. but that aside, swapping it indiana jones style with a best guess equivalently weighted bag of sand at the 30' max range for mage hand (assuming the object is no more than 10 lbs anyways)
Comments
DM: Ok.
Player: WHAT DID YOU ROLL?!
DM:
How far away are you standing?