You could try Bintel's UHTC cleaning fluid - they make it themselves - the formula is on their
product webpage and it does not contain shellite. I've made my own stuff in the past but usually end up making it too watery, and use something stronger eventually.
The rest of this post may be more than you wanted ...
For application, each to their own, but I prefer dabbing/blotting rather than spraying.
I suggest not using tissues. Our (Australian) tissues are derived from wood and therefore contain cellulose fibres, and there's advice around that 'harsh' cellulose fibres will damage optics. I understand that 'cotton' tissues in other countries contain actual cotton. On the other hand, Bintel say they use tissues ... so go figure.
I have my doubts about 'cotton' balls, even synthetic ones, but I have not used 'replacement pads' as you suggest. Still, I'd be wary as something 'cotton' could still be relatively harsh depending how it's made. I don't know the perfect solution, but I lean toward super-soft microfibre (beware
cheap microfibre) lens cleaning cloths, which will cost a bit. At least they're re-usable. Camera stores ought to carry good quality lens cloths.
FYI - I've played around with a few brands of lens wipes and the only one (so far) that seems 'good enough' for astro optics is Zeiss wipes, but I'd only use them on eyepieces and a corrector plate or objective out in the field where they're convenient.
Technique is also important - e.g. don't re-use a wipe/tissue and present a clean portion on each
short wipe.
We no doubt all have different ideas about how to clean our optics but, hopefully, my version helps a bit. I'm still learning.
