You could clean it with something else, but I would definitely use the K&N filter oil to oil it up again after cleaning it.
1969 Four door Saloon Old English White 1275 with ported head and HS4 carb. Wolseley 1500 front brakes. Currently off the road with a leaky master cylinder!
Cleaning kit is around £14, but it will clean quite a few filters, so would probably work out about £2 a time - hardly expensive. They should however be cleaned a bit more frequently than people do. Refer to website as indicated previously.
when i had my A-series i just washed it out in the sink and then re-oiled it with the special K and N oil spray can. Seemed to work fine (although i'm not sure if that whats your supposed to do ) and the can was only few dollars.
I had a mechanic once, he used parrifin on the filter. he well and truly wreck that filter on me. Needless to say i don't use that mechanic anymore. so my advice do what it says on the tin,
Your filter would have cost a few bob, £14 costs a lot less than a new filter.