Fifty gives you the room to get, ..., creative, yeh we'll go with creative with your work. Say wrap the spigot of a full five gallon gas can with a pound of material and set a 90 minute timer to snag the enemy first responders.
Attach an accelerometer to a bouquet of flowers with a cap plugged into 4 oz of material. The finder can forget about the date he had planned.
These are examples are hypothetical only. Past performance is not indicative of future performance (maybe). Your Mileage May Vary.
SpyNavy
Garde la Foi, mes amis! Nous nous sommes les sauveurs de la République! Maintenant et Toujours!
(Keep the Faith, my friends! We are the saviors of the Republic! Now and Forever!)
LonePalm, le Républicain du verre cassé (The Broken Glass Republican)