Crude nanotubes prepared (a) single-wall, by laser ablation and (b) multi-wall, by carbon vapor deposition (CVD), were heated 0.5 h at 600degreesC to remove fullerenes, treated 0.75 h with 15% H2O2 and washed 43 h in 2M HNO3 to oxidize amorphous C and residual catalyst, filtered in countercurrent in 2M HCl (17 h) and 0.1M HNO3 (7 min), and heated at 800degreesC to remove the residual solvent Catalytic metals, 15.4% Ni, 15.5% Co, were removed down to 0.1-1 wt.%. The template effect of metal catalyst particles was evident informing new C structures.