Cabin air filter substitutes

Anybody tried any substitutes for the stock cabin air filter? I live far from dealer or decent supply house, and wonder if there is a good substitute for the cabin air filter.

HEPA filters are commonly available for household vacuum cleaners, and have a fairly high flow rate. Likewise are cut-to-fit re-usable filters for forced air household heating/AC systems, especially the kind that use static electricity to attract and hold dust and pollen. These can be cleaned by squirting with a garden hose. Or, perhaps one of the filters for the engine air cleaner could be adapted for cabin air filtration use.

Before I mail-order a stock Bosch cabin air filter, I'd sure like to know what, if any, substitutes the others have tried.

Suggestions?

Mail order two of them... and any other parts you may need to save on shipping... if you reach their threshold of free shipping. BMA only has $50 threshold.

Take them out(mine came in two parts) brush the big stuff off , turn your fan on full with the filter housing open to clear the leafs etc that will have gathered there. Givethem a wash, I recommend Daz , dry it really well(most important), microwave if your in a rush.

You can tell how clean youve got it by the amount of reduction in blow between, filter in and no filter,remember even a new one will reduce the flow by a quarter or so.

If getting the parts is difficult, like you or you are cheap , like me, this does work.

I just bought by '90 535i, so don't know yet if it has a cabin filter, but reportedly that model year does not.

Anyhow, there are lots of good air filters around, used for HEPA air filters, for household use in HVAC systems, etc. In my house, we have a cut-to-fit re-usable filter for the central air/heat system. That filter comes in ~2' X 3' size, so you trim it to fit whatever size your furnace needs. Re-usable, it traps airborne crud by static electricity. To clean it, just disassemble and hose it off, then re-assemble and re-install.

Seems to me that this might actually be as good as or even better than (in terms of filtration efficiency) the much more expensive Bosch cabin filter for BMWs, especially as it can be re-used indefinitely.

Does anybody know the DIMENSIONS of the Bosch cabin air filter?