If it is an exposed rated lamp, then I would say yes this is probably safe.
But assuming it is an enclosed rated lamp (as most are), then I would say maybe. If the lamp is used (or you don't know it's history), I would not at all run it in the open. Technically even a brand new lamp can explode with a severe enough manufacturing defect, but I haven't seen that.
Explosion is always a risk, but if you shield the lamp or shield yourself you should be relatively safe even with an old lamp.
will be ineffective!