How to actually use a hand warmer (3-min activation guide)

Three steps. Three minutes. Eight hours of heat. Here's how to activate a PREF*RE hand warmer correctly — plus the small mistakes most people make.

Step 1: Rip open

Tear open the foil outer wrapper. Don't open it until you're ready — the chemistry is air-activated and starts as soon as oxygen hits the iron.

Common mistake: opening the wrapper hours before you need warmth. The pouch starts oxidizing immediately. By the time you put it on, you've already burned 30-60 minutes of useful heat.

Step 2: Shake well

Shake the inner pouch a few times to mix the iron, salt, water, charcoal, and vermiculite. About 5-10 vigorous shakes does it.

Common mistake: not shaking. The pouch will still warm up but more slowly and less evenly. Shaking accelerates the reaction by exposing more surface area to oxygen.

Step 3: Get heated

Drop the pouch where you need warmth. It reaches full ~62°C temperature in about 3 minutes and stays warm for 8+ hours (12+ for ULTRA).

Where to put a pouch

Inside a glove or mitten. Inside a coat pocket. Inside a hoodie kangaroo pouch. On your desk against a keyboard wrist rest. Inside a sleeping bag at the foot. Inside boots between sock and shell. On your lower back for systemic warmth.

Where NOT to put a pouch

Don't sleep on a pouch — heat is steady but it's still heat over 8 hours. Don't put it directly against bare skin under tight clothing for the full duration. Don't seal it in an airtight ziplock during use (it needs to breathe).

How to dispose

Spent pouches go in compost (99% biodegradable contents). The outer foil wrapper is recyclable. PREF*RE is one of the few hand warmers that fully breaks down in standard composting conditions.

RIP OPEN. SHAKE WELL. GET HEATED.