In 1991 Croatia became independent state after SFR Yugoslavia broke up. At the start of the civil war one third of croatian territory was occupied by serbian troops which formed their "Republic of Serbian Krajina".
At that time, there were no ex-Yugoslavian military factories located in free territory of Croatia, so almost all Croatian factories which had civil line of production before the war started to produce tens of different fragmentation hand grenades for Croatian army.
In 1991 most of these grenades were very primitively made, despite the fact that they were actually factory produced.
The main reason was that there was no time for detailled testing and for making complicated grenade fuzes. Military explosives like TNT and plastic explosives at that time were not easily available. Civilian explosives for mining were used from construction companies, and at the beginning fuzes were made using slow-burning pyrotechnical fuze with detonator No.8 also taken from croatian construction and mining companies.
Various pipes and materials were used for making bodies of that grenades
Next stage in production of croatian war-made grenades was making fuzes using practice VBR M75 fuzes confiscated from ex-Yugoslavian military bases in Croatia. Croatian engineers started substituting practice detonators from these fuzes with live croatian made detonators. Again the quality and reliability of that detonators varied from those which were local improvisation to those which were mass produced and detail tested.
The last stage in production of croatian war-made grenades were grenades like copy of M75, CETINKA, croatian M93 grenade and last variants of BIM grenade which were totally made of plastic.
After end of the war in 1995, all croatian war-made grenades from croatian army depots were destroyed and just M93 type stayed in army depots as official croatian post-war grenade.
During the war in former-Yugoslavia, several field improvisations were made by the soldiers themselves.
Plastic explosives was sometimes available and as you can imagine, every sort of "container" would suffice.
Goran provided info on the following Croatian devices : pepsi cola can , Vitezit charge w/nails , "Cedevita".