Alamun farin allo wani nau'in alkalami ne wanda aka kera musamman don amfani akan filaye marasa fa'ida kamar farar allo, gilashi. Waɗannan alamomin sun ƙunshi tawada mai bushewa da sauri wanda za'a iya goge shi cikin sauƙi da busasshiyar kyalle ko gogewa, wanda ya sa su dace don rubutu na ɗan lokaci.
