Note 1 - Summary of Significant Accounting Policies - Sales by Product Line (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Net Sales	$ 32,637,484	$ 12,232,088
Ceramic Diesel Particulate [Member]
Net Sales	5,652,686	6,536,085
Liquid Filters [Member]
Net Sales	25,464,614	5,264,663
Plastic Products [Member]
Net Sales	895,203
Development Projects [Member]
Net Sales	$ 625,981	$ 431,340

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration