A device for measuring an amount of dirt , the device comprising: a receiver configured to receive a sample collector , the sample collector having a front surface and a back surface , wherein a dirt sample is attached to the front surface of the sample collector ; a first contact configured to be placed in contact with the front surface of the received sample collector at a first contact point and a second contact configured to be placed in contact with the front surface of the received sample collector at a second contact point, the first and second contact being electrically conductive; an electrically conductive surface ; an aligner configured to position the electrically conductive surface in contact with the back surface of the received sample collector , wherein, when the electrically conductive surface is positioned by the aligner : a first part of the electrically conductive surface is placed in contact with the back surface of the sample collector at a point transverse to the first contact point on the front surface ; and a second part of the electrically conductive surface is placed in contact with the back surface of the sample collector at a point transverse to the second contact point on the front surface ; the device further comprising a resistance meter configured to measure an electrical resistance between the first and the second contact , wherein, when the first and second contact are placed in contact with the front surface and the electrically conductive surface is placed in contact with the back surface , the measured electrical resistance between the first and second contact represents the amount of dirt of the dirt sample, the represented amount of dirt being situated on the front surface of the sample collector between the first and second contact . a receiver configured to receive a sample collector , the sample collector having a front surface and a back surface , wherein a dirt sample is attached to the front surface of the sample collector ; a first contact configured to be placed in contact with the front surface of the received sample collector at a first contact point and a second contact configured to be placed in contact with the front surface of the received sample collector at a second contact point, the first and second contact being electrically conductive; an electrically conductive surface ; an aligner configured to position the electrically conductive surface in contact with the back surface of the received sample collector , wherein, when the electrically conductive surface is positioned by the aligner : a first part of the electrically conductive surface is placed in contact with the back surface of the sample collector at a point transverse to the first contact point on the front surface ; and a second part of the electrically conductive surface is placed in contact with the back surface of the sample collector at a point transverse to the second contact point on the front surface ; the device further comprising a first part of the electrically conductive surface is placed in contact with the back surface of the sample collector at a point transverse to the first contact point on the front surface ; and a second part of the electrically conductive surface is placed in contact with the back surface of the sample collector at a point transverse to the second contact point on the front surface ; the device further comprising a resistance meter configured to measure an electrical resistance between the first and the second contact , wherein, when the first and second contact are placed in contact with the front surface and the electrically conductive surface is placed in contact with the back surface , the measured electrical resistance between the first and second contact represents the amount of dirt of the dirt sample, the represented amount of dirt being situated on the front surface of the sample collector between the first and second contact . <EOS>