Historical restoration work requires immense attention to detail. The job also calls for a light touch in most cases. Consequently, many projects will need non-abrasive restoration techniques. You might be unsure about what these are or how they may fit into a project so here's a look at both issues.
What Is Non-Abrasive Restoration?
Every historical object accumulates some dust and even grime over time. One of the great questions of historical restoration is, "How much effort should go into removing unwanted stuff from items?" Likewise, there's a question of how much original paint, varnish, or polish should come off.
The goal of non-abrasive restoration isn't to answer that question, but to provide an option that minimizes the risks regardless of what your answer is. If there are bits of rust on the outside of a metal piece, a non-abrasive process can gently remove the rust without messing with the polish and patina. A restorer also can fill cracks and holes using techniques that don't subtract material from the object.
A major argument for non-abrasive techniques in historical restoration is to avoid using reductive processes. Think about sharpening a chef's knife. A chef's knife can afford to lose lots of metal due to sanding, polishing, and honing. In the cooking industry, this has the advantage of allowing a chef to always maintain a razor-sharp edge on the knife.
However, great chefs brutally reduce the mass and dimensions of their knives over time. Suppose several generations of restorers took the same approach to sanding a wooden table. Eventually, there wouldn't be much of the table left. Particularly, the exterior wouldn't be the original one because the table had been so thoroughly reduced.
The textures of materials are also important. Polishing a wrought iron gate will certainly clean the metal up. Unfortunately, it'll also take the texture out of the old iron. When people touch the iron, it won't have the same character that it once had.
Stripping a historical artifact also can damage the possibility of future discoveries. Many objects have multiple layers of paint, for example. Thanks to modern technologies, it's usually possible to scan through the layers and see what's underneath. However, someone had to leave those layers there for decades or centuries for modern researchers to get that chance. Today's restorers need to preserve those layers so future generations with emerging technologies will have the opportunity for further discoveries.