Combine

Some things can be combined to gain more mass, for example Wood scrap, hot Iron Lumps, Rye and others.

To Combine: Activate the first item (double click when it's in your inventory), then right click the second (identical) item and select Combine.

You can also combine more than two items at once. For this to work, activate any one item but the first in a pile of identical things, then right click the first entry (the one with a -/+ sign) and select combine. This will combine the item you have selected with the first 9 from the top (not counting the one you selected) into one item with the combined weight and the average QL of the combined items.

Note: Combining will reduce the total value of the items if they are not all the same QL, because Combining uses a linear average, but prices in the game are not linear. (Prices are quadratic so a quadratic sum would be more accurate than a linear average.)