The Olivetti Lettera 35 was designed by Mario Bellini and introduced in 1972. Its mechanical design was derived directly from the Olivetti Lettera 32, using a well-proven mechanism first introduced in 1963. The same mechanism was also used in the Olivetti Dora, Olivetti Valentine, and Olivetti Lettera DL (Lettera Deluxe).
The body is entirely metallic and consists of three die-cast aluminum parts: the lower shell, the upper shell, and the ribbon cover. The upper and lower shells interlock mechanically at multiple points and, together with their rounded geometry, provide exceptional resistance to impacts, provided the shock affects the frame rather than the carriage. Manufactured in Olivetti's factories in Spain, Mexico, and Yugoslavia, the Lettera 35 was available exclusively in a matte beige finish. It weighs 5.4 kg, measures 32 × 35 × 11 cm, and was supplied with a remarkably sturdy plastic carrying case weighing an additional 1.7 kg. A more portable version, the Olivetti Lettera 35i, was also produced. It featured a more compact body that retained the same robust construction and was supplied with a practical shoulder bag made of fabric. This model achieved remarkable commercial success throughout the South American market.
To remove the stubborn dirt accumulated over decades of neglect, traditional methods such as kerosene and brushes are often insufficient. Residues like dried correction fluid, eraser debris, hardened grease, and biological deposits require a more advanced approach. For this reason, a custom-built ultrasonic cleaning tank is employed, specifically designed for typewriter restoration. Using cavitation generated by high-frequency waves, microscopic bubbles implode against the components, providing a deep mechanical cleaning action enhanced by a mild soap solution. After ultrasonic treatment, all parts are rinsed in white petrol to remove residual moisture and prevent oxidation before lubrication and reassembly.
At the end of the restoration, the typewriter undergoes a complete functional test. A final test certificate—typed on the machine itself, signed, and stamped—is issued as proof of successful inspection and completion of the service.
