From the BBC:
Europe's air industry has called for an urgent review of flight bans imposed because of volcanic ash from Iceland.
The bodies representing most European airlines and airports have questioned the need for the unprecedented curbs, which affect millions of travellers.
Airlines that have carried out test flights say planes showed no obvious damage after flying through the ash.
While understanding that not all volcanic ash are made equal, my answer would be No. Some ash may be safer than others but I would not want to be the test subject.