Actually, alcohol is a better antiseptic than it is a sterilant or disinfectant, but it is better than nothing and your 70% solution is better than the 50%-60% solutions commonly sold, though you can often find 92% solutions if you call around.....
Strange as it may seem, manufacturers of silicone rubber caulks recommend 92% alcohol for prepping surfaces where silicone caulk is to be used, not for its antiseptic abilities, but for its ability to remove oils & residues that might inhibit proper adhesion of the silicone.....
What did the bird(s) that previously used the cage die of.....some pathogens can lie dormant for extended periods and with some, alcohol is little better than rinsing an item with plain water.....but.....that said, I would replace the wooden perches...most of the perches supplied with most cages are too small in diameter for the birds that will be using them...take your thumb and forefinger, touch them together, then open them so you have a semi-circle, with a gap of 3/4 inch, a bird gripping a perch like that would have much better purchase than where its talons meet on the back side or where they just go half-way around.....
Replacing wooden perches is cheap enough, you can find wooden dowels, in oak & softer woods, up to about 1.25 inches in diameter at your local home improvement store, large hardware store or even Michael's carries them.....just be sure to cut to the right length and to notch each end like the original perches.....
Here's an older link on disinfecting...I've got another file that is better at everyday disinfecting, but can't find it right off, but this one hits all the major points:
CDC - Disinfection & Sterilization Guideline
isinfection - HICPAC