1, nyuma yo gukoresha imimero yicyuma igomba gushyirwa mukibanza cyabigenewe, ikabikwa mu ruganda ruhumeka, rwumye, rufite isuku, ukoresheje intoki.

2, ubuso bugomba guhora burinda ingese, ntibyemewe muri acide, alkali, umunyu, imyuka ya chimique no kubika amazi.

3, birabujijwe kubika ubushyuhe bwo hejuru.

4, guhora usukura ibice bizunguruka, amavuta asanzwe, kugirango wirinde guterana kwumye, ibintu bivangavanze.