We will present new geomagnetic paleointensity results obtained as part of an ongoing multidisciplinary project (paleomagnetism, archaeology, experimental petrology, petrography and radiogenic dating) focused on slag material from southern Israel and Jordan. Additionally, we suggest a better resolution for a long standing archaeological dispute concerning the question about the oldest smelting furnace in the world (site 39B in Timna). Quenched copper-slag material from archaeological sites is a novel and highly promising medium to be used in paleointensity experiments. Its magnetization is carried by ultra fine grained magnetite and was acquired during initial quenching, often behaving nearly ideally during the paleointensity experiment. One of the richest archaeometallurgical regions in the eastern Mediterranean is located in the southern Levant, on both sides of the ‘Arava valley that separates the modern states of Israel and Jordan. Metalworking activities cover a time span of more than six thousands years, beginning in the 5th millennium B.C., a date that coincides with innovations in metallurgy in many parts of the Old World. We analyzed 77 copper-slag samples from 28 archaeometallurgical sites employing the elaborated IZZI experimental protocol which is derived from the Thellier-Thellier method. Anisotropy of anhysteretic remenance experiments were carried out to correct the results. Using strict data selection criteria, 35 samples yielded acceptable results for about a 45% success rate, which is extremely high percentage for this kind of experiments. The data gained hitherto shows a fluctuated field behavior, with relatively low field intensity during the 6th millennium B.P. and a conspicuous peak around 3,000 B.P. These trends agree with the global world-models and are in excellent agreement with data from northern Syria. Good paleointensity results from archaeological sites with poor or disputed dating can contribute to the archaeological discussion. Such is the case of site 39B in Timna Valley, Israel, which some scholars claim it to be the oldest copper smelting furnace in the world, dating to the Chalcolithic period, around 6 thousands years B.P. This claim has been under debate for more than forty years, as arguments for later periods, mainly the early Roman and early Iron Age, have been raised. Our paleointensity results imply multiperiodical use, starting indeed as early as the Chalcolithic period.