Try with this, not tested. It will not remove breakables that are only destroyable by activating them via button.
PHP Code:
#include <amxmodx>
#include <fakemeta>
#pragma semicolon 1
new PLUGIN[] = "";
new AUTHOR[] = "";
new VERSION[] = "0.00";
public plugin_init()
{
register_plugin(PLUGIN, VERSION, AUTHOR);
new pEnt = get_maxplayers();
while((pEnt = engfunc(EngFunc_FindEntityByString, pEnt, "classname", "func_breakable")) > 0)
{
if(!(pev(pEnt, pev_spawnflags) & SF_BREAK_TRIGGER_ONLY))
engfunc(EngFunc_RemoveEntity, pEnt);
}
}