Eight builds that turn rubbish into rescue. Do each one once, on a calm weekend, so your hands remember when your head is busy panicking.

Bottle water filter

30 min · easy

You need

• 1.5 L PET bottle and a knife
• Clean cotton cloth
• Charcoal from a wood fire, crushed (not BBQ briquettes)
• Fine sand and gravel, rinsed until the water runs clear

1. Cut the bottom off the bottle. Turn it upside down, neck pointing down, cap off.
2. Stuff cloth into the neck as the last layer.
3. Add, from the neck upwards: charcoal, then fine sand, then gravel on top. Coarse at the top, fine at the bottom.
4. Pour water in slowly. Throw away the first two batches; they carry charcoal dust.
5. Boil what comes out. This makes water clearer, not safe.

Box-fan air purifier for the haze

45 min · easy

You need

• A fan with a flat, square face
• Four MERV-13 filters the same size as the fan
• Cardboard and lots of duct tape

1. Tape the four filters into an open cube, the airflow arrows on each pointing inward.
2. Tape a cardboard square over the bottom.
3. Sit the fan on top, blowing upward and out, so air is pulled in through the filters.
4. Seal every gap. Add a cardboard ring around the fan’s corners so air can’t sneak back.
5. Run it in the clean room. Swap the filters when they turn grey. It’s a well-known DIY design, not a certified purifier, so don’t leave it running unattended for days.

Brick rocket stove

20 min · easy · outdoors only

You need

• 16 to 20 bricks
• Two metal bars or a grill to rest the pot on
• Dry sticks, thumb-thick

1. Lay a square of bricks on flat ground, leaving a one-brick gap in the front as the fuel door.
2. Stack four or five more layers on top as a closed square chimney.
3. Rest the bars across the top, with space for the flame and smoke to escape around the pot.
4. Feed sticks in sideways through the door. The chimney sucks air in and burns them hot, with far less wood and smoke than an open fire.

Sardine-tin oil lamp

10 min · easy

You need

• An empty, washed sardine or tuna tin
• Cooking oil
• Cotton string or a strip of cotton T-shirt
• A square of foil or a bent paper clip to hold the wick

1. Pour 1 cm of oil into the tin.
2. Push the wick through the foil or clip so it stands up, 3 to 5 mm above the oil, with the rest soaking below.
3. Light the tip. It burns steadily and smells faintly of goreng.
4. On a metal tray, away from curtains, never unattended, never near kids. A lamp is a small fire you’ve agreed to babysit.

Two-bucket toilet

15 min · easy · essential

You need

• Two buckets with lids
• Heavy bin bags
• Sawdust, cat litter or dry soil
• An old toilet seat, or a pool noodle slit down one side

1. Line each bucket with a bag. One bucket for wee, one for everything else. Keeping them apart cuts the smell dramatically.
2. Cover each use in the solids bucket with a scoop of sawdust or litter.
3. Tie off bags at two-thirds full and store them outside in a lidded bin.
4. Wash hands every time. The least Instagrammable and most important build in this book.

Tarp rain catcher

10 min · easy

You need

• A clean tarp
• Cord
• A clean bucket
• One small stone

1. Tie three corners high and the fourth low, over the bucket.
2. Put the stone in the middle so the tarp forms a funnel.
3. Let the first few minutes of rain rinse the tarp, then start collecting.
4. Boil before drinking. Malaysia will refill it by tomorrow afternoon.

Tarp A-frame and hammock

30 min · medium

You need

• Tarp 3×3 m, hammock with mosquito net
• 30 m paracord, 4 tent pegs or sticks
• Two trees about 4 m apart

1. Tie a tight ridge line between the trees at head height.
2. Drape the tarp over it and peg the four corners out at roughly 45 degrees.
3. Hang the hammock below the ridge line with a gentle sag, about 30 degrees on each rope.
4. Tie a short string to each hammock rope as a drip line, so rain running down the rope drips off before reaching you.

The kampung lastik

1 hr plus a week drying · medium

You need

• A Y-shaped fork from a guava (jambu batu) branch, about thumb-thick
• Latex tubing or flat band (sports and fishing shops), or an old inner tube
• A small leather pouch: an old shoe tongue works
• Strong string or dental floss

1. Cut the fork with arms about 10 cm long. Strip the bark and dry it in the shade for a week.
2. Cut a shallow notch near the top of each arm.
3. Tie one end of each band into a notch, wrapping tightly with string.
4. Tie the other ends through the pouch.
5. Wear eye protection. Aim at tin cans, and at the troop of macaques eyeing your bins. Never at people.