The visual examination of the pottery pieces from tell el-Shobak in Qalyubia, Egypt showed that the pottery samples formed by potter wheel method. It also shows soot, salts, cracking, lost parts and surface sediments as shown in ( Fig. 1a-b). Damage aspects were due to heterogeneity of mineral components [24]. Some researchers attributed the damage to burial in the soil [25] .The exposure environment (post excavation) increases severity of damage [26]. Polarized microscope proved that the used clay is Nile clay due to presence of biotite, muscovite, pyroxene and plagioclase [27] as shown in ( Fig. 2:7). PLM examination confirmed presence of some additives such as sand, lime stone powder and grog, which are common materials in Egyptian pottery [28] as shown in ( Fig. 2:7). PLM examination also proved presence of surface treatment by slip layer. Sometimes, the ancient Egyptian used red wash [29]. The examination also showed presence of some internal cracks due to pressures and strains. Pottery texture was coarse for the first sample and medium to coarse for the second sample as in Fig. (2:7). The texture is shape and relationship of the granules to each other [30]. The texture varies according to clay, formation technique, surface treatment, and firing [31]. SEM Examination showed presence damage aspects, such as cracks, gaps, fractures, crystallization of salts and stains, as in shown in ( Fig. 8a-b &9a-b.( Cracks in our studied pottery are due to internal pressures and crystallization of salts [32]. SEM- EDX confirmed medium burning of the first pottery for presence of carbon dioxide with a high percentage 15.17% for the surface area and low percentage 1.95% for the core area. Good burning for the second pottery sample, where the percentage of carbon reached 1.78% for the surface and 0 .66% for the core area. This indicates that the burning atmosphere was oxidizing atmosphere for pottery samples, as shown in (Table 1).SEM- EDX confirmed presence of calcite, chloride, and sulfate salts, where the percentage of chlorine in the first pottery sample reached 16.19% for the surface and 4.45% for the core. For the second sample, the percentage of chlorine reached 4.46% for the surface as shown in (Table 1). EDX also proved presence of calcium, where the percentage of calcium in the first pottery sample reached 9.43% for the surface and 8.25% for the core. For the second sample, the percentage of calcium reached 14.77% for the surface and 6.48% for the core as shown in (Table 1). The percentage of sulfur in the first pottery sample reached 3.13% for the surface, while the percentage of sulfur in the second pottery sample reached 3.43% for the surface, which confirms presence of chloride and sulfate salts as shown in (Table 1). The crystallization of salts is one of the most important manifestations of damage because pottery artifacts is a hygroscopic material that absorbs saline water from the soil [33].XRD proved presence of calcite as one of the temper additives [34]. The analysis also proved presence of gypsum and carbonates due to burial soil [35]. XRD analysis also revealed presence of albite, quartz and calcite in the archaeological site sample, which confirms that the soil is calcareous clay soil as shown in (Table 2). Differential thermal analysis "DTA" of the first pottery sample showed the firing temperature was 726.78°C for the first pottery, where the hydroxyl group of mechanical combined water for clay was lost at firing temperature from 31.21. °C to 79.60°C. The minerals changes increased by hydroxyl group loss of chemical combined water of clay, burning and oxidation of organic matter from 109.80°C to 164°C and then the minerals changes were significantly increased due to decomposition of carbonate into CaO and Co2, organic residues and chlorides from 388.83 to726.78 (Fig. 14) .for the second pottery, the firing temperature was 737.80°C, where the hydroxyl group of mechanical and chemical combined water of clay, burning and oxidation of organic matter from 294.72°C to 408.56°C and then the minerals changes were significantly increased due to decomposition of carbonate into CaO and Co2, organic residues and chlorides from 479.89 737.80°C (Fig. 14) [36] .
Treatment and maintenance
The study of the various examinations and analyzes to our studied pottery artifacts from tell El-Shobak in Qalyubia, Egypt proved presence of soil sediments, as well as chloride, sulfate salts, and soot. Pottery objects suffer from breaking and loss of some parts of body
Pottery pieces characterized by weakness and lack of durability. According to damage conditions, results of examinations and analyzes and scientific studies in this field. Restoration, treatment and maintenance processes applied on our studied pottery artifacts.
Recording and Documentation
The pottery objects (the vessel and plate) excavated from tell El-Shobak in Qalyubia, Egypt were photographed as shown in (Fig. 16a,b) to determine damage aspects or deterioration state before treatment..
Cleaning
The pottery pieces cleaned of soil deposits mechanically using various brushes. The sediments that were highly adherent to the surface were cleaned using metal scalpels. The cleaning method was carried out from top to bottom not to scratch the pottery body [37]. It has given positive results, as shown (Fig. 17a-f ).
Chemical cleaning carried out in order to clean the various soil deposits using organic solvents. A mixture of acetone and toluene in a ratio of 1:2 respectively was prepared; chemical cleaning for our studied objects done locally for each piece separately according to [38]. Soot sediments was removed using hydrogen peroxide 20 % [39], the calcareous sediments were cleaned using EDTA, that applied as a poultice [40], cleaning results as shown in figure ( Fig. 18a-f )
Removal of Salts
The salts were removed mechanically using brushes and scalpels .cleaning was done under lenses "6X" not to scratch the pottery according to [41]. Then, this was followed by making poultice of distilled water to remove soluble salts such as halite salts, according to [42]. EDTA poultice applied to remove calcareous deposits of carbonates and sulfates salts [43].
Consolidation
The pottery artifacts extracted from Tell el-Shobak in Qalyubia were strengthened using nano silica 1% according to (Saad, 2018) [44]. Poultice method was applied in strengthening process according to (Dei 2013) [45].
Assembling
The initial assembly process for broken pottery started to find out the places of fracture of pottery sherds according to (Elghareb, 2007) [46].
Then, the pottery sherds were assembled using paralloid B 72 dissolved in toluene 50% [47]. Assembling results as in (Fig. 19a, c).
Filling Gaps
After the assembly process, it was noticed that the pottery artifacts were missing some parts. Replacement was applied using a mixture of microballoon and Pottery powder in a ratio of 2: 1. First, alumina paper applied under the missing part to match the lost part. Second, completion material was prepared, which is a mixture of microballoon and Pottery powder in a ratio of 2: 1. Third, the completion material applied according to (Saleh et al. 2020) [48]. After an hour, it was shaped and polished using various molding tools. Thus, the pottery pieces restored the artistic and archaeological form that it was before burial in the soil. Results shown in (Fig. 20a, c).
After replacement of our studied objects, the pottery artifacts were strengthened, protected and isolated using Paralloid B 82 (3%) by brushing. Pottery artifacts were ready to museum display (Fig. 21a, b).