You can buy 20 for 16.42 Euros here. Unfortunately, S/H is probably 164 Euros. Fischer Scientific in Ottawa list a number of cleanroom swabs available in smaller quantities; I must visit and have a look. if you can get them for $1 USD each, I'll take 50. Only 950 more takers required. LOL
Last one drive i need to clean, i used HUBY-340 CA-008 applicator and clean room wipe, this one costed me around 4€ / 100 pc.
Used it on several case so far without problemes with Isopropanol and acetones.