Buying & sorting

Kiloware and Stamp Mixtures: What You Actually Get When You Buy Stamps by Weight

Kiloware is the hobby's great slow pleasure: a box of used stamps still on envelope paper, bought by weight, sorted over many evenings. It won't make anyone rich, and listings that suggest otherwise are selling a dream. But for learning, building a worldwide or topical collection, hunting postmarks and perfins, or simply enjoying the sort, nothing beats it. This guide explains the different kinds of mixtures, how to read a listing, and a workflow that turns a pile of paper into a tidy collection.

What kiloware is (and isn't)

The word comes from the old practice of selling used stamps by the kilo. Today "kiloware" usually means used stamps clipped from envelopes and parcels, still on their backing paper, sold by weight. Related terms you'll see in listings:

Kiloware isn't a shortcut to rare stamps. It's a way to accumulate a lot of genuine, postally used material cheaply and learn from it. Our article on why most old stamps are not rare is a healthy reset before you buy.

Why collectors still love it

• Learning identification: sorting hundreds of stamps teaches inscriptions, designs and printings faster than any book. Pair it with our guide to identifying a stamp's country.
• Topical collecting: mixtures are full of birds, flowers, ships and people. Every lot fills gaps.
• Postmarks: on-paper stamps keep their cancels, often with town names and dates. Postmark collectors and town specialists love kiloware.
• Perfins and precancels: business mail mixtures are the natural habitat of perforated initials. See our perfins guide.
• Varieties and printings: long-running definitive series come in many printings, papers, perforations and shades. Bulk duplicates let you compare them side by side.
• Trading stock: duplicates become currency at clubs and swap groups.

How to read a kiloware listing

Listing language varies from precise to meaningless. Here's what to look for and what to discount.

Good signs

• A stated origin: a specific country, a mission, a bank or office source.
• "Unpicked" or "as received", ideally with a reason to believe it, such as a seller who explains where it came from.
• Photos of the whole lot, not just the best few stamps on top, plus close-ups of a random handful.
• Neat trimming with a small margin of paper around each stamp, which protects perforations.
• A clear statement of weight, and whether that includes packaging.

Warning signs

• "Rare", "valuable" or "investment" in the title of a bulk lot.
• Photos that show only a few attractive stamps spread out, with no view of the bulk.
• Stamps trimmed tight to the design, cutting into perforations.
• "Picked" or no information at all about whether anyone has already been through it.
• Heavy proportions of whole envelopes padding the weight without being described.

To compare how lots are described, browse kiloware on paper, mission mixtures and bank mixtures on eBay. For research, completed sales tell you more than asking prices: try sold unpicked kiloware.

A sorting workflow that saves hours

The biggest mistake new kiloware buyers make is soaking everything at once. Sort first; soak second.

1. Do a first pass on paper. Spread a handful at a time on a clean table. Pull out anything that looks unusual: perfins, interesting postmarks, high denominations, older stamps, anything you don't recognize.
2. Check for whole covers. If any complete envelopes are mixed in, look at them before cutting or soaking. The postmark, rate or route may make the whole cover more interesting. See look at the cover before soaking.
3. Separate self-adhesives. Many modern self-adhesive stamps don't release cleanly in water. Most collectors keep them on neatly trimmed paper rather than risking damage.
4. Separate colored paper. Stamps on red, green or dark envelope paper can pick up dye in water. Soak those separately, or skip them.
5. Soak the rest in batches, in clean cool water, then dry face down between absorbent paper and press flat. Our full method is in how to soak stamps off paper safely.
6. Sort by country, then by series, into glassine envelopes or a stock book. Put duplicates in a separate trading box.
7. Record what's interesting as you go: postmark towns, perfin patterns, possible varieties to check later.

A few practical cautions

• Mold and dust. Kiloware that has sat in damp basements can carry mold. If a lot smells musty or shows spots, sort it in a ventilated space, consider a dust mask, and don't put it near your main collection.
• Insects and debris. Old boxes sometimes include unwelcome residents. Check the packaging when it arrives.
• Postmarks first, then cleaning. Never try to "clean up" a heavy cancel. Postmarks are part of the stamp's history and often the most interesting thing about a kiloware stamp.

Choosing a source: single country or worldwide?

The source of a mixture shapes what you'll learn from it.

For children and new collectors, an off-paper worldwide mixture is usually the gentlest start: no soaking, lots of variety, and immediate sorting. Graduate to on-paper kiloware once the soaking routine feels comfortable.

Keeping the results organized

A mixture can easily turn into a second, unsorted mixture. Give every stamp a destination: your main collection, a duplicates box, a "to research" envelope, or a trading stock book. Label glassines with country and series as you fill them, and keep the "to research" pile small enough to actually get through. If storage is the bottleneck, our stock book vs album guide will help you choose.

How much should you buy?

Less than you think, at first. A modest amount of on-paper kiloware takes many hours to sort properly, and sorting is the whole experience. Start with a small lot from a country or source that interests you, work through it completely, and decide whether you enjoyed the process before buying more.

If you like a particular source (one country's commercial mail, for instance), buying from the same seller repeatedly often works well, as long as quality stays consistent. If you mostly want variety, alternate between countries and mixture types.

What to do with the leftovers

You will end up with duplicates, sometimes hundreds of the same definitive. Options: trade them at a club, pass them to a youth program, keep them for printing and shade studies, or bundle them for resale as off-paper mixtures. Some collectors donate surplus to clubs or charities; see our donation guide.