Note 2 - Inventory

12 Months Ended

Dec. 31, 2019

Notes to Financial Statements

Inventory Disclosure [Text Block]

NOTE

2

- INVENTORY

Inventory consisted of the following at

December 31, 2019

and

December 31, 2018:

	2019			2018
Furnace parts and supplies	$	621,991		$	596,806
Raw materials		2,125,921			1,659,826
Work in process		1,624,499			1,691,175
Finished goods and filtration systems		1,492,135			1,596,042
Reserve for excess and obsolescence		(665,308	)		(1,111,794	)
Net Inventory	$	5,199,238		$	4,432,055

Inventory valuation adjustments for excess and obsolete inventory is calculated based on current inventory levels, movements, expected useful lives, and estimated future demand of the products. The valuation reserve has declined in

2019

compared to

2018

due to the scrapping of several slow-moving products previously written off.